DICTIONARY 


ICAL  DRAWING 


LIBRARY 

OF  THE 

UNIVERSITY  OF  CALIFORNIA. 

Class 


UNIVERSAL    DICTIONARY 

OF 

MECHANICAL  DRAWING 


NET  "BOOK  NOTICE 

It  is  intended  that  this  book  be  sold  to  the  public 
at  the  advertised  price,  and  is  supplied  to  the 
trade  on  terms  that  will  not  allow  of  discount 

The  Engineering  Ne&s  "Book  "Dept. 


BY 

3RGE    H.    FOLLOWS 

>esign  and  Mechanical  Drawing,  Carnegie  Technical  Schools,  Pittsburg 
of  Standard  Division  of  the  Engineering  Department, 
;house  Electric  and  Manufacturing  Company 


FIRST     EDITION 


•  FIRST    THOUSAND 


NEW   YORK 

THE  ENGINEERING  NEWS  PUBLISHING  COMPANY 

1906 


GENERAL 


Copyright,  1906,  by 
THE   ENGINEERING   NEWS   PUBLISHING   COMPANY 


J.    r.    T  *  P  L  e  v    c  o. 


CONTENTS 


PAGE 

I.  INTRODUCTION  AND  AN  ALPHABET y 

II.  LETTERS  AND  LETTERING 

•J 

III.  FIGURES   AND    DIMENSIONS I5 

IV.  PROJECTION    AND    PROJECTED    VIEWS J? 

V.     SECTIONING   AND    SECTIONAL    VIEWS 2I 

VI.     FINISHES   AND    THE  'FINISH    MARK 26 

VII.     DIMENSIONING 

*••••••••*.         2Q 

VIII.     THE    RECORD    STRIP       . 

"     «iy 

IX.     NOMENCLATURE   AND    WRITTEN    MATTER 

*  i>J 

X.     CHECKING 

»*•**.**•«          5O 

XL     STANDARD    DATA 

•  •  •  •  •  •  •  .  .5* 

XII.     EXAMPLE    DRAWINGS 


PREFACE 

In  a  paper  on  "  Mechanical  Drawing  in  the  Modern  Drafting  Room  "  read  before  the  Engineers'  Society  of  Western 
Pennsylvania,  in  June,  1903,  I  dwelt  with  some  emphasis  upon  the  importance  of  uniformity  in  what  I  then  termed  the 
"  dictionary  "  features  of  mechanical  drawings.  This  paper  was  reprinted  by  the  Society  as  a  pamphlet,  and  later  was 
published  in  Engineering  News  and  in  several  other  of  the  leading  engineering  periodicals  both  here  and  in  England. 
The  great  interest  taken  in  the  subject  was  entirely  unexpected.  In  all,  something  over  seventy  letters  were  received  con- 
taining favorable  comments,  letters  not  only  from  all  parts  of  the  United  States  but  from  Canada,  England,  France, 
Holland,  and  even  from  New  Zealand  and  South  Africa.  Among  these  letters  were  several  from  universities  and  colleges 
asking  if  it  were  not  possible  to  put  together  a  "drawing  dictionary"  as  a  text-book  for  the  use  of  our  schools  and  col- 
leges. It  seemed  to  be  the  unanimous  opinion  that  such  a  dictionary,  dealing  with  mechanical  drawing  as  a  language, 
would  be  appreciated  by  teachers,  students,  and  drafting  rooms  alike.  Finally  the  editor  of  Engineering  News  suggested 
that  I  prepare  such  a  dictionary  to  be  published  first  in  that  journal  and  afterwards  as  a  text-book.  This  book  is  the  result 
of  that  suggestion.  It  has  been  written  with  the  hope  that  the  drafting  fraternity,  as  well  as  teachers  and  students  of 
mechanical  drawing,  will  accept  it,  as  far  as  it  goes,  and  use  it  as  a  basis  for  the  writing  of  the  language. 

The  author  has  for  many  years  believed  that  such  a  book  should  be  written  to  insure  reasonable  uniformity  in 
the  drawings  made  by  different  men  in  different  places. 


G.    H.    F. 


August   15,    1906. 


CHAPTER    I.     INTRODUCTION    AND   AN    ALPHABET. 


SOME  two  thousand  four  hundred  years  ago  a  philosopher  and  his- 
torian known  to  the  world  as  Diogenes  of  Apollonia  said:   "It 
appears  to  me  that  he  who  begins  a  treatise  ought  to  lay  down  principles 
about  which  there  can  be  no  dispute." 

2.  As  this  article  is  the  first  of  a  series,  and  is  written  with  a  hope 
that  the  complete  series  will  result  in  an  acceptable  ' '  drawing  dictionary  " 
for  general  use,  it  seems  only  right  to  begin  by  laying  down  the  princi- 
ples upon  which  the  character  of  the  dictionary  is  to  depend.     I  do  not 
presume  to  think  that  the  principles  are  new  or  that  I  am  able  to  lay 
them  down  in  such  a  way  as  to  leave  no  room  for  dispute;  but,  believ- 
ing that  the  manner  of  presenting  a  subject  is  fully  as  important  as  the 
subject  itself,  it  seems  best  to  begin  in  this  way  so  that  those  who  read 
the  series  critically  may  stand  on  common  ground  and,  looking  at  each 
feature  from  the  same  general  position,  pool  their  ideas  to  some  useful 
purpose. 

3.  Mechanical  drawing  is  a  "language." 

This  is  the  first  principle  that  I  would  lay  down,  and  it  is  the  general 
one  upon  which  arguments  will  be  based  and  in  keeping  with  which 
criticisms  should  be  made;  it  means  that  mechanical  drawing  can  be 
compared  with  any  other  language,  English,  for  instance;  for  although 


it  cannot  be  spoken  or  heard,  it  can  be  both  written  and  read,  written 
well  and  read  well,  written  badly  and  read  badly.  And,  just  as  the 
ability  to  write  or  read  (that  is,  understand)  good  English  depends 
upon  a  knowledge  of  English  as  a  language,  so  the  ability  to  make 
or  read  a  good  drawing  depends  upon  a  knowledge  of  drawing  as  a 
language. 

4.  When  we  think  of  English  as  a  language,  we  have  in  mind  an 
alphabet,  words,  and  sentences;  and  going  further  to  the  written  lan- 
guage as  we  find  it  in  our  libraries,  we  add  chapters  and  books. 

5.  There  is  a  broad  and  useful  analogy  between  mechanical  drawing 
as  a  language  and  English  as  a  language. 

6.  This  is  the  second  principle  that  I  would  lay  down.     There  are 
many  ways  of  expressing  the  analogy,  but  the  following  is  sufficiently 
suggestive  and  will  suffice  for  the  present : 

Lines  are  analogous  to Letters 

Views  to Words 

Projected  views  to Sentences 

Drawings  to Chapters 

Sets  of  drawings  to Books 


OUTLINE. 


Lines   should  be    varied  in   weight  and  size    fo   suit   the   character  of  drawing. 
Heavy 


HIDDEN    LINE 
CENTER    LINE 


Medium 
Thin 


DIMENSION  LINE 
PROJECTION   LINE 
BREAK    LINES 


Thin 


Thin 


— —     F^or    the    visible    bounding  lines   of  a    view. 
For    the   hidden  bounding   lines   of  a   view. 

For  indicating    the  position    of  an  imaginary    unbroken 

line  of  no   thickness. 

— v     For  indicating    the  path  of  a  dimension,  and   the  points 
or  surfaces  "between   which  measurement  is  to  be  made. 

For  projecting   a  dimension  line   to  a  .convenient  position 

clear  of  a   view;    also   for  projecting  in  general. 

For  indicating  that  for  convenience    some  part   of  a 
view  is  broken  away:   "I.    For  all  materials    except  when 
"2  is  preferable  for   wood  broken   across   the  grain. 

For  indicating  a  path  of  motion. 

For  indicating  a  uniform  repetition  or  continuation  of 
some  shape  when  a  completed  layout  is  not  necessary 
and  would  be  expensive. 

SUB   LINE — For  indicating  either  an   alternative  position   of  the 

some  piece  or  the  bounding  lines  of  a  substitute  piece. 

ADJACENT    LINE — —        For  the  bounding  lines  of  what  is   adjacent    to  a  view. 


Heavy 


Uneven 
*2 


PATH    LINE 
DITTO    LINE 


Thin 


Medium 


ALLOWANCE    LINE 
LIMIT    LINE        — 


CUTTING    LINES 


Medium 
Very  heavy 

•M^^^^^B^^^^^^M      • 

Medium 


Very  heavy 
*2 


For  indicating   a  special  allowance   for  finish. 


•      For   indicating   a  surface    or  position   beyond   which 
nothing   should  project. 


For  indicating    the  position    of  a    cutting   plane  in 
connection    with    a   sectional    view  :     *  I.    When    the 
plane    does   not    coincide   with  a   center    line.    "2.  when 
the  plane   coincides    with  a  center  line;  also    when    it 
is   not  desirable    to   have   the  fine  passing    through  a 
view. 


Special  Lines:       When    a    Una   is   used  for  a    special  purpose,  (except    when   conventional)    there    should   be   a   note 
explaining  its  meaning. 

Broken    Lines:      There    should   be  clear    space    between    the  parts    of  all   broken   lines;  otherwise    they   have    too  nearly 
the  appearance  of  full  lines. 


FIG.  1.    THE  ALPHABET  OF  LINES. 


y.  Teachers  and  students  alike  should  make  practical  use  of  this 
principle,  as  inducing  a  true  conception  of  the  relative  values  of  the 
parts  of  drawings,  and  as  enabling  the  subject  as  a  language  to  be 
studied  and  taught  intelligently. 

8.  Knowledge  of  English  is  obtained  from  books  written  with  the  ex- 
press purpose  of  teaching  it  as  a  language,  beginning  with  an  alphabet 
of  letters  and  the  spelling  of  words,  and  ending  with  the  teachings  of 
scholars  and  thinkers  from  whose  writings  we  receive  instruction  re- 
garding the  construction  of  sentences  and  the  arrangement  of  ideas,  as 
from  the  late  Herbert  Spencer's  "Philosophy  of  Style." 

9.  So  far  as  English  is  concerned,  the  result  of  having  an  accepted 
dictionary  and  the  carefully  written  teachings  of  scholars  is  that  books 
written  by  one  man  can  be  read  and  understood  without  difficulty  by 
other  men,  and  that  there  is  general  uniformity  about  the  mechanical 
features  of  all  real  books.     By  mechanical  features  I  mean  the  type, 
the  page  numbering,  the  division  into  chapters,  the  insertion  of  illus- 
trations, the  position  and  general  arrangement  of  title  page,  the  index- 
to  contents,  and  the  "build"  of  the  book  itself.     So  that  when  we  com- 
pare two  English  books,  even  though  they  are  by  different  authors  and 
were  printed  in  different  countries,  we  find  the  same  alphabet,  the  same 
spelling,  sentences  of  similar  form,  the  same  rules  of  composition  fol- 
lowed, and  in  general  the  same  mechanical  features,  both  inside  and 
out.     The  advantage  of  this  uniformity  is  twofold:  The  reader  can 
turn  from  one  book  to  another  without  being  confused  by  differences 
in  spelling,  word  meanings  or  general  arrangement;  and  books  can  be 
placed  side  by  side  on  the  same  shelf  without  offending  our  sense  of 
what  is  reasonable. 

10.  The  object  of  the  proposed  drawing  dictionary  is  to  bring  about 
a  similar  state  of  things  in  connection  with  mechanical  drawings. 


11.  At  the  present  time,  there  being  no  generally  adopted  dictionary, 
our  universities,  colleges  and  schools  teach  almost  as  many  drawing  lan- 
guages (or  rather  "dialects")  as  there  are  teachers:  for  in  one  little  way 
or  another  each  teacher  has  his  own  independent  idea  as  to  what  is  best. 

12.  So  far  as  drafting  rooms  themselves  are  concerned,  it  goes  with- 
out saying  that  each  has  its  own  pet  "dialect,"  or  more  than  one;  new 
draftsmen  being  generally  expected  to  learn  the  practice  of  a  "room" 
by  observing  existing  drawings  and  doing  likewise. 

13.  On  all  accounts  it  seems  that  there  is  a  real  need  for  a  Universal 
Drawing  Dictionary,  and  though  any  attempt  to  make  the  first  one 
perfect  and  complete  would  fail,  I  believe  it  is  possible  to  compile  one 
that  will  be  valuable  at  the  outset,  that  will  be  improved  and  become 
much  more  valuable  in  time,  that  will  from  the  first  enable  the  school 
or  college  course  better  to  prepare  a  man  for  actual  work  in  the  modern 
drafting  room,  and  that  many  drafting  rooms  will  be  only  too  glad  to 
adopt. 

14.  The  third  principle  that  I  would  like  to  see  accepted  is  in  the 
nature  of  a  definition: 

15.  Mechanical  drawing  is  a  language  oj  lines,  rieu's,  dimensions, 
signs  and  abbreviations,  notes  and  explanatory  matter,  all  /or  the  positive 
conveying  oj  exact  information. 

1 6.  The  reader  should  particularly  note  the  clause,  "all  for  the  positive 
conveying  of  exact  information."     A  shop  drawing  is  intended  not  as 
an  expression  of  opinion  to  be  argued  about,  but  as  a  set  of  instructions 
to  be  obeyed.     A  drawing,  therefore,  should  contain  all  necessary  in- 
formation and  nothing  else:  and  every  statement,  whether  made  by 
means  of  lines  or  words,  or  combinations  of  lines  and  words,  should 
be  absolutely  free  from  ambiguity  and  as  clear  and  easy  to  understand 
as  the  knowledge  and  common  sense  of  the  draftsman  can  make  it. 


17-  In  general,  the  proposed  dictionary  will  cover  the  following 
features:  Lines,  letters  and  lettering,  figures  and  dimensions,  projection 
and  projected  views,  sectioning  and  sectional  views,  methods  of  dimen- 
sioning, conventional  signs  and  their  meanings,  finish  designations  and 
marks,  conventional  methods  (the  draftsman's  idioms),  some  suggestions 
regarding  designations  and  abbreviations  of  names,  lists  on  drawings, 
a  few  example  drawings,  and  suggestions  regarding  the  compiling  of 
standard  data. 

18.  No  attempt  will  be  made  to  have    the   dictionary  cover  shop 
>\>tems,  because  to  be  universal  in  character  it  must  be  good  for  any 
method  of  conducting  business,  just  as  the  English  dictionary  is  good 
for  any  method  of  handling  a  subject. 

19.  In  this  article  a  proposed  alphabet  of  lines  is  presented.     In 
presenting  this  and  other  features  of  the  dictionary,  I  shall  endeavor 
to  state  what  the  requirements  are,  to  give  all  necessary  definitions,  and 
by  argument  to  show  that  what  is  proposed  is  reasonable. 

20.  Here  Fig.  I  names,  illustrates,  and  defines  the  lines,  while  Fig. 
2  is  supplementary  to  the  definitions  given  in  Fig.  i  and  is  somewhat  in 
the  nature  of  an  example  drawing  in  which  all  the  lines  are  used. 

The  requirements  of  the  alphabet  are: 

1.  That  it  shall  be  complete. 

2.  That  the  names  of  the  lines  shall  be  short  and  that  they  shall,  as 
far  as  possible,  indicate  their  use. 

3.  That  the  character  of  the  lines  shall  be  such  that  they  can  be 
readily  distinguished  one  from  another. 

4.  That  the  lines  that  are  to  be  used  the  most  shall  show  the  greatest 
contrast,  and  be  the  easiest  to  draw. 

21.  The  lines  shown  in  Fig.  i  are  designed  as  a  "  set "  for  pen  work,  to 
give  satisfactory  contrast,  and  are  all  drawn  to  the  same  scale;  it  is  thus 


their  relative  values  that  are  indicated,  not  a  series  of  lines  for  mechan- 
ical copying.  It  is  no  more  possible  to  have  one  weight  and  size  of 
line  suitable  for  all  drawings  than  it  is  to  have  one  kind  and  size  of  type 
suitable  for  all  books.  If  this  set  of  lines  were  reduced  or  enlarged  by 
photography  the  same  proportions  and  contrasts  would  be  maintained. 
This  indicates  how  the  lines  are  to  be  used:  No  matter  what  the  scale 
of  a  drawing  there  should  be  the  same  contrasts.  In  pencil  work  the 
contrasts  will  necessarily  be  less  striking,  but  they  can  be  maintained 
to  a  considerable  degree  when  desirable. 

22.  THE  OUTLINE.— There  is  really  no  room  for  argument  about  this 
line,  except  with  regard  to  varying  its  thickness  to  give  the  effect  of 
shading.     Such  shading  lends  some  appearance  of  solidity  to  a  view, 
but  being  expensive,  it  is  very  little  used  now  in  the  drafting  rooms  of 
manufacturing  concerns.     However,  the  fact  that  it  is  used  sometimes, 
as  in  government  drafting  rooms,  where  cost  is  not  so  closely  figured, 
in  patent  office  drawings,  and  for  certain  classes  of  illustrating,  makes 
it  best  always  to  include  it  in  a  course  of  study.     The  ability  to  shade 
drawings  is  not  only  valuable  in  itself,  but  the  study  of  it  affords  ex- 
cellent practice  in  the  use  of  drawing  instruments. 

23.  THE  HIDDEN  LINE. — The  illustration  and  definition   do   not 
require  any  special    comment,  this    being  the  form  already  in    gen- 
eral use. 

24.  THE  CENTER  LINE. — The  unbroken,  thin  line  is  considered  the 
best,  not  only  because  it  is  strictly  in  keeping  with  the  meaning  and 
purpose  of  the  line,  but  because  being  the  line  from  which  principal  di- 
mensions are  laid  off,  and  in  which  centers  are  located,  it  must  be 
accurate;  and  no  other  line  can  be  drawn  as  accurately.     The  same 
line  may  be  used  for  any  imaginary  line  that  is  to  answer  the  same 
general  purpose  as  a  center  line;  pitch  lines  for  instance. 


10 


'enter  line 


u 


''•^ — Allowance  line 
Center  line     ('  f  •  ^       I 


B 


SlDE    Vl£W  " -Cutting  line  "2 


tt 

j      Lx^^'  Projection  line 

XT 

r*—  Cutting  line  */ 


SECTIQH  A  B 


-  Center  line 


Sub  line 


Outline 


Center  line  I 


Hidden  line 


Sub  line 


j 


Projection         Dimension  tine 
line 


r 

L 


Ditto  line 


Outline 


-Projection  line 


line 


SECTION  C  D 


SHADED  OUTLINE 


Outline 


FIG.    2.      INDICATING   HOW  THE  TEN    LINES  OF  THE  ALPHABET  ARE  USED. 


25.  THE  DIMENSION  AND  PROJECTION  LINES. — In  mechanical  draw- 
ings, unnecessary  intersections  of  lines  should  be  avoided;  this  helps  to 
clearness,  and  is  one  reason  for  having  the  dimension  and  projection 
lines  broken,  so  that  they  may  cross  one  another  without  actually  inter- 


alphabet  of  lines,  like  that  of  the  dictionary  itself,  is  more  closely 
associated  with  the  reading  of  drawings  and  the  making  of  tracings 
than  with  the  original  work  of  the  draftsman  proper.  An  original  pen- 
cil drawing  bears  somewhat  the  same  relation  to  the  tracing  and  blue- 


FIG.  3.    SHOWING  SIDE  VIEW  AND  SECTION  A  B  FROM  FIG.  2  AS  THEY  APPEAR  WHEN    ONLY  TWO  LINES  ARE  USED. 


secting.  A  projection  line  should  never  quite  touch  a  bounding  line; 
bounding  lines  stand  out  much  more  clearly  if  they  are  not  interfered 
with. 

26.  The  other  lines  do  not  call  for  any  individual  comment;  they  are 
all  used  in  Fig.  2,  where  the  lines  of  each  view  are  named.  In  the  Section 
A  B  and  the  side  view  belonging  to  it,  ten  of  the  fifteen  lines  are  used. 
By  way  of  contrast  and  with  the  idea  of  showing  how  very  necessary  it 
is  to  have  an  alphabet  of  lines,  these  same  two  views  are  repeated  in 
Fig.  3,  but  with  only  two  lines  instead  of  the  ten.  The  value  of  this 


12 


print  made  from  it  as  an  author's  manuscript  does  to  the  printed  book. 
In  both  cases  the  original  is  the  work  of  one  man  and  is  not  intended 
for  the  eyes  of  the  public,  while  the  result  is  to  a  large  extent  a  mechan- 
ical product,  and  is  for  the  reading  of  an  unlimited  number  of  men. 
And  just  as  the  duty  of  a  publisher  is  to  put  the  author's  manuscript 
into  such  book  form  that  the  public  may  read  with  ease  what  the  author 
has  written,  so  it  is  the  duty  of  the  tracer  to  put  the  draftsman's  work 
into  such  shape  that  others  may  easily  read  and  understand  it. 

27.  But  although  as  directly  affecting  work  done,  the  dictionary  is 


more  especially  for  the  tracer  and  the  "reader,"  the  draftsman,  too, 
must  be  minutely  familiar  with  it,  not  only  because  a  large  part  of  his 
work  is  the  reading  of  drawings,  but  because  he  must  by  notes  or 
otherwise  on  his  original  drawings,  however  rough  they  may  be,  insure 
against  misunderstandings  on  the  part  of  the  tracer. 

28.  The  broad  purpose  of  the  dictionary,  and  of  the  alphabet  of  lines 

.  as  part  of  it,  is  to  make  it  easier  for  all  concerned  to  read  tracings  and 

shop  prints,  and  thus  to  save  time  every  time  a  drawing  is  referred  to. 


This  is  the  immediate  practical  gain  to  be  looked  for  from  the  general 
adoption  of  a  drawing  dictionary.  There  is  also  a  gain  of  another  and 
no  less  important  kind:  Mechanical  drawing  will  cease  to  be  something 
to  "pick  up,"  like  bicycle  riding,  and  will  take  its  proper  place  as  a 
universal  language  to  be  systematically  studied;  so  that  whether  it  is 
the  draftsman  that  draws  or  the  some  one  else  that  reads,  there  will  be  as 
little  chance  as  possible  for  the  misinterpretation  or  partial  understand- 
ing of  something  that  ought  to  be  as  plain  as  day. 


CHAPTER    II.     LETTERS   AND    LETTERING. 


29.  The  style  of  lettering  used  in  the  printing  of  this  paragraph  is 
particularly  rich  in  letters  that  give  shape  and  individuality  to  words. 
Take  the  word  "sprightly,"  for  instance:  Seven  of  its  nine  letters  either 
rise  above  or  fall  below  the  line,  so  that  the  complete  word  has  a  shape 
peculiar  to  itself.     We  recognize  it  at  a  glance,  just  as  we  do  the  face  of 
some  one  we  know;  no  more  need  to  spell  the  word  out  letter  by  letter 
than  to  examine  the  face  feature  by  feature;  one  look  at  the  general 
shape  is  enough. 

30.  In  reading  this  style  of  lettering  we  unconsciously  recognize  the 
words  by  their  shape,  and  read  the  sentence  phrase  by  phrase  rather 
than  word  by  word;  so  that  the  meaning  is  easily  absorbed  as  the  eye 
passes  along  the  line. 

31.  THE  STYLE  OF    LETTERING    USED    IN    THIS    PARAGRAPH    AND 
THIS  IS  A  STYLE  THAT  UNFORTUNATELY  HAS  HAD  A  LONG  RUN  OF 


13 


FAVOR  IN  DRAFTING  ROOMS  FOR  NOTES  ON  DRAWINGS-ROBS  THE 
WORDS  OF  ALL  SPECIAL  SHAPE  OR  PECULIAR  OUTLINE,  AND  GIVES 
THEM  A  PAINFULLY  MONOTONOUS  SIMILARITY.  IN  READING  THIS 
LETTERING  WE  UNCONSCIOUSLY  SPELL  THE  WORDS  OUT  LETTER 
BY  LETTER,  AND  READ  THE  SENTENCES  WORD  BY  WORD  INSTEAD 
OF  PHRASE  BY  PHRASE.  SUCH  READING  IS  TIRESOME,  BECAUSE 
THE  MIND  IS  SO  BUSY  DECIPHERING  WORDS  AND  PHRASES  THAT 
BY  THE  TIME  THE  END  OF  A  SENTENCE  IS  REACHED  THE  FULL 
MEANING  OF  IT  IS  RATHER  MORE  THAN  LIKELY  TO  BE  LOST. 

32.  All  notes  on  drawings  should  be  in  a  style  of  lettering  that  is 
easy  to  read;  this  is  the  first  requirement.     And  the  lettering  should 
be  easy  to  write,  both  well  and  uniformly. 

33.  In  Fig.  4  two  styles  of  letters  and  lettering  are  shown:  One  for 
all  notes,  and  one  for  titles  and  headings.     The  lower-case  letters  have 
the  advantage  already  described  of  giving  individuality  and  shape  to 


CAPITAL  LETTERS:  ABCDEFGHIJHLMNOPQRSTU  v  w  x  Y  z  & 


LOWER  CASE  LETTERS:  abcdefghijkimnopqrstuvwxyz&  —§j^^il4 e"ualspoces 

THE  O^AL  in  the  lower  case  letters  is  shaped  thus:(J,  and  inverted  thus:  //;   this  oval  or 
part  of  it  is  used  in  the  following  letters  in  the  manner  indicated: 

a  be  de@b<j  ma  pq  $  a 

THE  SLOPE  for  all  letters  is  3  in  8,   thus:  fa    Example     (fa 

In  A,V,  W  and  Y  the  slope  is  obtained  thus:  A  not  /j,    V  not  I/,    fr  not  W,     Y  not  k 

CAPITAL  LETTERING:    Examples:    SECTION  A  B.    PATTERN  LIST.    END  VIEW. 

This  style  of  lettering  is  for  titles  and  headings. 

LOWER    CASE  LETTERING.'    Example:    Make  pattern  to  this  line. 

This  style  of  lettering  is  for  everything  except  titles  and  headings. 

SIZES:       Standard:    *^END    V/EW'^>    '-pMake  pattern  to  this  line.~ 

,_i_  "IS  *!<•  * 

Small:  *a£V£    VlEW~.  Make  pattern   to   this  line. ^L 

^  '3k 

Large:        WE^ND    VlEW^    '^Make  pattern  to  this  li 


T 

When  there  is  not  room  for  the  standard  use  the  small  size. 

The  large  size  should  be  used  only  when  it  is  advisable  to  give  special  prominence  to  a  heading  or  note. 

SPACING:    STANDARD—  SMALL  LARGE 

.-r-ln  this  example,  letters~,iwords  !r>  this  example,  letfers,  words  . 
'*J&ond  lines  are  correctly  spaced.  e^TMffa?f7Z&fS£Su          '"     ™IS     exat7 
The  letters  of  a  word  should  be  reasonably  dose  together.             letters,   words 
be  reasonably  close  together.                       Paragraphs  should  be  Indented      /•  -,,-~,W/i/ 
Paragraphs  should  be  indented  as  '"^"ated  here'                              lmeS    are    Correctly 
as  illustrated  here. 
-•$•- 

FIG.  4.    LETTERS  AND  LETTERING. 


words;  notes  written  in  this  style  are  very  easy  to  read.  The  letters 
are  so  free  from  ornamental  or  superfluous  features  that  they  are  equally 
easy  to  write;  and  the  ideal  simplicity  of  their  construction  leaves  so 
little  room  for  variety  in  the  shaping  that  different  men  readily  learn  to 
write  them  alike.  The  capital  letters,  though  unsuitable  for  notes, 
serve  well  for  titles  and  headings. 

34.  The  writer  believes  that  for  mechanical  drawing,  sloping  letter- 
ing is  better  than  vertical.  An  argument  used  by  those  who  favor  the 
vertical  lettering  is  that  there  is  only  one  vertical  as  against  any  number 
of  slopes,  and  that  it  should  therefore  be  easier  to  teach  and  get  uni- 
formity with  the  vertical  lettering.  But  as  a  matter  of  fact,  it  is  prob- 


ably easier  to  get  a  sufficiently  uniform  slope  than  a  sufficiently  exact 
vertical,  because  a  very  slight  deviation  from  the  vertical  is  noticeable. 
In  the  average  mechanical  drawing  there  are  so  many  truly  vertical  lines 
to  compare  with  that  the  eye  more  readily  detects  a  deviation  from  the 
vertical  than  from  any  given  slope.  Then  again  the  sloping  lettering 
stands  out  more  clearly  by  contrast  with  the  vertical  and  the  horizontal 
lines  of  the  drawing.  However,  in  this  matter,  which  is  really  one  of 
style  not  in  any  way  affecting  the  language  proper,  drafting  rooms  may 
be  left  to  make  their  own  choice.  In  this  "dictionary"  no  attempt  will 
be  made  to  settle  questions  of  style. 


CHAPTER    III.     FIGURES    AND    DIMENSIONS. 


35.  In  the  average  mechanical  drawing  the  dimensions  play  the  prin- 
cipal part,  not  only  because  they  directly  guide  and  control  the  work 
in  the  shop,  but  because  many  of  them — what  are  generally  termed 
the  working  or  finish  dimensions — have  to  play  an  active  part  during 
the  entire  life  of  the  drawing. 

36.  By   the   term   dimension   as  used  here  is  meant  the  complete 
construction — the  figure,  the  notation  marks,  the  line  and  the  arrow- 
heads. 

37.  I  would  lay  particular  emphasis  upon  the  fact  that  a  working 
dimension  is  "alive"  as  long  as  the  drawing  is  in  use;  so  that  if  it  is 
difficult  to  read,  doubtful,  or  misleading,  when  the  drawing  is  first 


made,  it  is  again  difficult  to  read,  again  doubtful,  or  again  misleading 
every  time  it  is  referred  to.  Thus  an  indistinct  arrow-head  or  a  3  that 
looks  like  an  8  is  in  the  first  place  a  possible  source  of  error,  and  if 
allowed  to  remain  may  become  a  permanent  source  of  trouble  and 
expense. 

38.  Every  dimension  should  indicate  with  unmistakable  clearness 
two  things:  First,  the  points  or  surfaces  between  which  measurement  is 
to  be  made;  second,  the  distance  to  be  measured.     These  are  the  chief 
requirements. 

39.  Fig.  5  deals  with  the  several  parts  of  a  dimension,  and  shows  a 
set  of  six  standard  constructions. 


EXPLANATORY :    By  the    term  "dimension"  is  meant  the  figure,    the    notation  marks,   the   line    and  the  arrow-heads, 
as   in   the  following  example: 

FIGURES:  1234567890 
THE  SLOPE  is  J  in  8,  thus :   f.\  -  f  ,      -»;«- : .       -^ —       -y  ^ , ^, 

AND  PROPORTIONS  '\^\ 

NOTATION   MARKS'     3-ff  ^means  a  distance  of  3  feet   6  inches.   The  marks  are  at  a  reverse  angle  of  45'  \. 

45—30-52   means  an   angle  of  45  degrees   30  minutes   52  seconds. 
Tht  minute  and  second  marks  have  tht  same  slope    as   the   figures. 

DISTANCES:   Examplts:    3*  7-5"   12"- 0^  £   J^"    j!  1416   ".7854     5*- 0*83  —f^= 

FRACTIONS:    Numerator  and  denominator  art  separated  by  a  horizontal  fraction  line. 

DECIMALS '     Tht  notation  mark  is  placed  vertically  above   the  decimal  point. 

PROPORTIONS 
THE  SlZE   of  the  figures   should  be  suited  to  the   other  ports  of  the  dimension,  and  shoula  i 

bt    chosen    with    discretion.       A   suitable  size  for  ordinary   work   is    £  ,    thus:    •* -^ 

When  immediately   connected  with    lettering,    the  size    should  be    the  same  as  that  f|T^ 

of  tht    capital  letters,    thus  i  l^\.,,^,      O  "7  y*  "7 C 

Aug.  3, 1904     fig.  28     Uwg.  234  7 O 


ARROW-HEADS!     •<—)  About   60*   made,  freehand.      Size  and  weight   to  suit   tht   other  parts  of  tht  dimension. 

CONSTRUCTIONS :    The  parts   of  a   dimension  can   be   arranged  in  six  different  ways,      constituting   what  may  be 
termed  a  s*t  of  standard  dimensions. 

— 


The  purpose  of  these  constructions  is  to  make  it  impossible  with  ordinary 
core  in  readi'ng  to  misunderstand  the  meaning. 

Each   construction   is   what  may  be   called  a  "common  sense"  arrangement- , 
and  is  subject  to  slight  modifications  as  indicated  in  I,  J  and  4. 

In  5  the,  reversed  arrow-heads    mean  to  outside  lines- 

In  6  it  is  clear   that  the  meaning  is  from  inside  line   to  outside  line. 

A  dimension  arrow-head  should  never  be  placed  so  that  it  is  interfered 
w7th  by  any  other  lint. 

, 


FIG.  5.     FIGURES  AND  DIMENSIONS. 


AO.  THE  FIGURES. — The  figures  in  a  drawing,  like  the  letters,  should 
be  entirely  free  from  ornamental  or  superfluous  features,  so  that  they 
may  be  both  easy  to  read  and  easy  to  write.  Those  given  have  the 
required  simplicity  of  construction  without  being  in  any  way  robbed 
of  their  individuality,  and  the  shapes  are  such  that  it  is  practically 
impossible  to  mistake  one  figure  for  another. 

41.  What  was  said  in  paragraph  34  about  the  use  of  sloping  lettering 
applies  here  to  the  sloping  figures.     If  sloping  lettering  is  adopted,  slop- 
ing figures  should  also  be  used. 

42.  NOTATION  MARKS. — The  peculiarity  of  the  notation  marks  for 
the  foot  and  inch  is  that  they  are  sloped  in  the  opposite  direction  to  the 
figures.     This  is  done  to  make  it  less  possible  for  a  mark  to  be  confused 
with  the  figure  i,  especially  in  connection  with  the  numerator  of  a  frac- 


tion.    Incidentally  this  reversing  of  the  marks  gives  additional  character 
to  a  dimension. 

43.  FRACTIONS. — The  writer  is  of  the  opinion   that  the  horizontal 
fraction  line  is  better  than  the  sloping  one,  not  only  because  it  is  less 
liable  to  be  scribbled,  but  because  it  makes  a  neater  looking  and  more 
compact  fraction. 

44.  DECIMALS. — The  position  of  the  notation  mark  is  of  importance. 
Placed  as  shown,  it  is  a  valuable  check  on  the  decimal  point. 

45.  CONSTRUCTIONS. — The  clearness  of  a  dimension  depends  largely 
upon  the  disposition  of  the  arrow-heads  and  dimension  lines  with  re- 
spect to  the  lines  representing  the  points  or  surfaces  of  measurement. 
The  constructions  given  will  bear  careful  study.     They  are  not  by  any 
means  an  insignificant  part  of  the  language  of  mechanical  drawing. 


CHAPTER    IV.     PROJECTION    AND    PROJECTED   VIEWS. 


46.  In  the  English  language  it  is  not  at  all  uncommon  for  a  word  to 
have  more  than  one  meaning.     Sometimes  the  several  meanings  of  the 
same  word  are  due  to  accident  and  cannot  be  clearly  traced  to  any  pos- 
itive source,  but  generally  by  stepping  back  through  the  forms  a  word 
has  had  in  different  languages  it  is  possible  to  get  at  its  earliest  form 
and  to  discover  its  original  meaning. 

47.  Many  of  the  words  we  use  have  their  "roots"  among  what  are 
known  as  the  dead  languages,  Latin  and  Greek;  while  the  origin  of 


others  is  even  more  remote.  Ruskin,  in  one  of  his  lectures,  speaks  of 
"words  of  true  descent,  of  ancient  blood,"  and  would  have  us  know 
the  history  of  all  such  words.  This  is  perhaps  expecting  too  much, 
but  there  is  wisdom  in  the  idea,  especial!}'  if  we  are  reading  to  acquire 
definite  knowledge.  If  under  such  circumstances  we  come  across  a 
word  that  has  a  vital  bearing  upon  the  subject,  and  we  are  not  quite 
sure  of  its  true  meaning,  it  is  wise  to  go  to  the  dictionary  and  look  up  its 
derivation.  We  have  examples  here  in  the  words  "project"  and  "pro- 


FIG.  8 


FIC,.  10. 


F~l  Q.l J:  Showing  fhre e  correct' groupings  of  the  some  set  of  views. 


18 


FIGS.  6  TO  11.      SKETCHES  ILLUSTRATING  THE  PRINCIPLES  OF  PROJECTION   DRAWING. 


jection,"  because  they  have  several  applied  meanings  and  because  it  is 
of  vital  importance  to  understand  their  true  significance  in  connection 
with  mechanical  drawing. 

48.  The  Century  Dictionary  tells  us  that  the  verb  "project"  is  de- 
rived from  the  Latin  " projectare,"  out  of  the  root  words  "jacere,"  to 
throw,  and  "pro,"  forth;  and  that  its  literal  meaning  is  "to  throw  out 
or  forth,  to  cast  or  shoot  forward."     The  significance  of  the  word  as 
applied  in  mechanical  drawing  is  "to  throw  forward  in  parallel  rays 
or  straight  lines."     And  " projection "  means  "either  the  act  or  the 
result   of   projecting   parallel  rays  from  the  surface  of  a  body  and 
of  cutting  these  rays  with  a  plane,  so  as  to  obtain  on  the  plane  a 
shape    corresponding    point    for   point  with    that  of  the  body."     (A 
"plane"  is  a  perfectly  flat  surface;  it  has  no  thickness,  and  is  there- 
fore transparent.)     In  mechanical  drawing  the  rays  are  called  "  pro- 
jection lines." 

49.  It  will  thus  be  seen  that  the  word  "project"  is  not  only  of  good 
and  ancient  lineage,  but  that  as  used  in  mechanical  drawing  its  true 
significance  is  quite  in  keeping  with  its  literal  meaning. 

50.  In  Fig.  6  a  "body"  is  represented  as  projecting  from  its  surface 
parallel  rays,  or  "projection  lines";  a  "plane"  is  placed  so  as  to  cut 
these  lines;  and  the  intersections  of  the  lines  and  the  plane  result  in  a 
"projection"  corresponding  in  shape  with  that  of  the  body. 

51.  In  mechanical  drawing  a  projection  of  this  kind  is  called  a  "view," 
meaning  that  it  is  the  "view"  that  would  be  obtained  by  an  observer 
stationed  on  the  same  side  of  the  body  as  the  projection  plane.     This  use 
of  the  word  view  is  of  course  conventional. 

52.  In  Fig.  7  the  same  body  is  represented  as  projecting  rays  in  three 
directions;  three  planes  are  interposed,  a  top  plane,  a  front  plane,  and  a 
side  plane;  and  three  projections,  or  views,  are  obtained,  which  it  would 


obviously  be  correct  to  call  a  top  view,  a  front  view,  and  a  side  view, 
respectively. 

53.  In  Fig.  8  the  three  planes  with  their  views  have  been  brought  into 
one  surface.     This  brings  the  "top"  view  "above"  the  front  view,  and 
the  "right"-side  view  to  the  "right"  of  the  front  view;  a  correct  group- 
ing.    Two  other  groupings,  equally  correct,  are  shown  in  Figs.  9  and 
10;  and  all  three  are  mechanically  reproduced  in  Fig.  n.     It  is  evi- 
dent that  each  grouping  embodies  the  same  principle  of  projection,  and 
has  precisely  the  same  meaning;  it  is  also  evident  that  Fig.  7  is  a  full 
and  complete  interpretation  of  each  group. 

54.  Thus  in  the  language  of  mechanical  drawing  a  solid  body  can 
be  accurately  and  definitely  represented  by  a  group  of  projected  views. 

55.  Unfortunately  the  method  of  projection  employed  in  the  above 
is  only  one  of  two  that  are  in  use  at  the  present  time.     The  other  is 
known  as  "first-angle"  projection,  and  this  "dictionary"  would  be  in- 
complete if  it  did  not  contain  something  akin  to  a  definition  of  it.     In 
geometry,  when  two  planes  intersect  at  right-angles  the  angles  are  des- 
ignated first,  second,  third  and  fourth,  as  numbered  in  Fig.  12.     First 
angle  projection  places  the  body  in  angle  No.  i  and  projects  a  "top" 
view  on  to  the  plane  "under"  the  body  and  a  view  of  the  "right"  side 
on  to  the  plane  to  the  "left"  of  the  body,  and  so  on;  that  is,  the  pro- 
jection lines,   instead  of  being  "thrown  out  from  the  surface,"   are 
"passed  back  through  the  body."     In  other  words,  the  body  is  supposed 
to  turn  itself  inside  out. 

56.  The  absurdity  of  this  method,  clearly  demonstrated  by  contrast 
in  Fig.  13,  led  to  its  being  generally  abandoned  in  this  country,  and  it  is 
to  be  hoped  that  the  true  method  will  eventually  supersede  it  universally. 

57.  True  projection  is  sometimes  called  "third  angle"  to  distinguish 
it  from  "first  angle."     The  name,  however,  is  not  only  superfluous, 


19 


FIG.  12.      SKETCH   ILLUSTRATING  "FIRST  ANGLE' 

20 


PROJECTION. 


but  can  easily  be  misleading,  because  no  matter  which  "angle"  the 
body  is  supposedly  placed  in,  or  how  many  planes  are  employed,  if 
true  projection  is  used  the  views  will  always  be'orthodox. 

58.  In  a  mechanical  drawing  every  view  should  be  projected  in  the 


into  its  proper  place,  a  special  view  may  be  drawn;  but  such  a.  view  must 
not  be  placed  as  though  it  were  projected  from  others,  but  must  be 
distinctly  separate  and  independent,  and  be  suitably  titled. 

59.  In  mechanical  drawing  a  group  of  views  is  a  complete  and  com- 


Tme  Projection  'First- Angle" Method. 

FIG.  13.      FIRST  ANGLE   PROJECTION   AND  TRUE   PROJECTION   CONTRASTED. 


orthodox  manner,  and  correct  grouping  should  never  be  sacrificed,  on 
the  plea  of  convenience,  to  any  mere  "arrangement."  If  it  is  impossi- 
ble because  of  the  shape  or  limited  size  of  a  drawing  to  project  a  view 


prehensive  "sentence"  (Paragraph  6,  Chapter  i)  and  if  one  of  the 
group  is  where  it  should  not  be,  it  amounts  not  merely  to  an  error  in 
spelling  but  to  a  misleading  statement. 


CHAPTER   V.     SECTIONING   AND    SECTIONAL   VIEWS. 


60.  SECTIONING. — This  is  a  subject  that  has  a  rather  interesting  his- 
torical side.  Time  has  made  such  sweeping  changes  in  the  work  of  the 
draftsman — due  largely  to  the  invention  of  blue  printing  and  other 
copying  processes — that  we  have  come  almost  to  forget  what  a  drawing 
of  a  generation  ago  was  like,  and  to  entirely  lose  sight  of  the  influence 


21 


that  some  of  the  old-fashioned  methods  have  had  upon  the  drawing 
of  to-day. 

6r.  Before  the  introduction  of  blue  printing,  the  "original"  drawing 
was  used  by  all  concerned,  and  was  quite  an  elaborate  and  expensive 
affair  compared  with  the  shop  print  of  to-day.  In  the  first  place  it  was 


Cast  Iron  Moll  table  Iron 


Cast  Steel  Wrought  Steel 


Wood-  With  and  across  the  groin. 

FIG.  14.      STANDARD  SECTION   LINING  FOR  DIFFERENT  MATERIALS. 
(Reproduced  from  Krinh.irdt's  "Technic  of  Mechanical  Drafting.") 


made  on  the  best  and  toughest  of  paper — it  had  to  be  to  stand  the  wear 
and  tear;  then  it  was  inked  in  with  genuine  "India"  ink  rubbed  down 
from  the  stick;  and  if  it  was  a  drawing  of  a  standard  machine  it  was 
shaded  with  the  brush  and  symbolically  colored  according  to  the  mate- 
rials of  construction.  Then  before  being  put  into  service  it  was  care- 
fully mounted  on  a  suitable  board  or  cloth  and  given  a  coat  of  shellac 
to  preserve  it  and  make  it  washable.  Such  was  the  work. of  some  of 
the  "old-school"  draftsmen  of  twenty-live  or  thirty  years  ago — very 
different  from  the  "product"  of  the  modern  drafting  room. 

62.  In  the  use  of  the  brush,  for  shading  and  for  the  coloring  of  sur- 
faces in  section,  the  old-time  practice  had  a  decided  influence  on  the 
line  sectionings  that  prevail  to-day.     When  colors  were  used,  cast  iron 
in  section  was  represented  by  an  even  wash  of  gray,  wrought  iron  by 
Prussian  blue,  steel  by  a  thin  wash  of  crimson  lake;  while  brass  was 
tinted  gamboge  yellow,  and  wood  was  imitated  in  both  color  and  grain- 
ing as  closely  as  the  draftsman  knew  how. 

63.  With  the  general  adoption  of  tracings  and  blue  prints,  shading 
with  the  brush  died  a  natural  death,  giving  way  first  to  line  shading, 
later  to  shaded  outlines,  and  finally  to  no  shading  at  all;  and  color  sec- 
tioning was  superseded  by  line  sectioning  as  used  to-day. 

64.  Now  it  is  necessary  to  bear  in  mind  that  when  the  custom  was 
to  represent  materials  by  symbolical  colors,  there  were  comparatively 
few  constructive  materials  in  use,  compared,  that  is,  with  the  far  greater 
number  and  variety  employed  at  the  present  time.     To  a  very  large  ex- 
tent cast  iron  was  then  simply  cast  iron,  brass  was  brass,  and  steel — 
what  little  there  was  of  it — was  not  used  in  so  many  grades  as  to  call 
for  a  special  set  of  symbols.    Thus  a  few  colors  were  able  to  represent 
the  materials  in  common  use  with  sufficient  precision.     So  also  when 
the  advent  of  the  blue  print  called  for  "lines"  in  place  of  "colors,"  it 


22 


was  not  necessary  to  have  any  great  number  of  symbolical  "section- 
ings."  Cast  iron  was  satisfactorily  represented  by  evenly  spaced  par- 
allel lines;  wrought  iron  by  alternate  thick  and  thin  ones;  steel  by  lines 
in  pairs;  brass  by  alternate  full  and  broken  lines,  and  so  on.  But  in 
later  years  the  additional  number  of  materials  employed  has  called  for 
some  ingenuity  in  devising  sufficiently  distinctive  sectionings;  the  writer 
has  seen  authorized  varieties  that  were  not  only  quite  difficult  to  pro- 
duce, but  painfully  uncomfortable  to  look  at. 

65.  Fig.  14  shows  a  set  of  sectionings  such  as  are  used  to-day  in 
many  drafting  rooms.     It  is  a  good  set  *  and  would  be  fairly  satisfac- 
tory were  it  not  that  materials  are  now  made  in  so  many  different  grades, 
and  there  are  so  many  alloys,  and  so  many  new  materials — or  old  ones 
modified  to  suit  special  kinds  of  service — that  it  is  no  longer  possible 
to  represent  materials  precisely  by  symbolical  sectionings. 

66.  Again,  many  of  the  big  manufacturing  concerns  now  have  their 
own  "official  specifications"  for  the  materials  they  purchase  or  pro- 
duce, such  specifications  covering  both  the  chemical  and  the  physical 
requirements.     On  drawings,  therefore,  it  is  becoming  customary  to 
call  for  a  material  either  by  full  descriptive  name  or  by  general  name 
and  specification  number.     Thus  a  bearing  metal  may  be  specified  as 
"No.  6  Alloy";  a  steel  may  be  "Axle  Steel,  Specification  No.  6140"; 
a  shaft  may  be  called  for  as  "Open-hearth  steel,  oil  tempered  and  an- 
nealed"; an  aluminum  bronze  may  be  known  as  "No.  15  Bronze"; 
and  so  on. 

67.  Symbolical  sectioning  then  is  no  longer  sufficient  in  itself  as  an 
indication  of  material. 

*  For  this  set  the  author  is  indebted  to  "  Reinhardt's  Technic  of  Mechanical 
Drafting,"  in  which  excellent  work  the  reader  may  find  a  comprehensive  treatment 
of  some  sixty-five  very  effective  individual  sectionings. 


68.  These  considerations  induced  the  writer  some  five  years  ago  to 
suggest  that  sectionings  be  used  to  indicate  not  individual  materials  but 
classes  of  material. 

69.  Fig.  15  gives  a  suggested  classification  and  a  set  of  suitable  sec- 
tionings.    Briefly  the  classification  is  well  expressed  by  the  meanings 
of  the  sectionings  themselves;  thus: 

No.  i  means  "Metal." 

No.  2  "  "Poured  into  place  hot." 

No.  3  "  "Poured  into  place  cold." 

No.  4  "  "Fibrous  or  flexible." 

No.  5  "  "Flexible  insulation." 

No.  6  "  "Wood." 

No.  7  "  "Stone  class." 

No.  8  "  "Liquid." 

No.  9  "  "Special." 

70.  For  the  principle  involved  in  this  classification  three  distinct  ad- 
vantages are  claimed: 

First:  There  are  so  few  sectionings  required  that  it  is  not  necessary 
to  use  any  that  are  at  all  difficult  to  produce. 

Second:  Each  sectioning  has  a  constant  and  definite  meaning. 

Third:  A  change  of  material  after  a  drawing  has  been  made  does  not 
necessitate  the  erasing  of  a  sectioning,  unless  the  new  material  belongs 
to  a  different  class,  which  will  very  rarely  be  the  case. 

7 1 .  What  may  almost  be  considered  as  a  fourth  advantage  is  illustrated 
in  Fig.  16,  where  by  suitably  varying  the  thickness  and  spacing  of  the 
"metal"  sectioning  lines  the  different  surfaces  show  good  contrast. 
This  contrast  or  "color  effect"  is  fully  equal  to  anything  that  can  be 


23 


The    sections   given   here  are    not  for    individual  materials,    but  are    for  indicating 
the    broad   classes  of  the  materials    used  in    machine    construction. 

The  thickness  and  spacing  of  the  lints  should  be  varied  to  suit  the  size  of 
the  surface    and  the  character  of  the  droning. 


i:  METAL: 


2'.  POURED  INTO 
PLACE  HOT: 


3:  POURED  INTO 
PLACE  COLD: 


41  FIBROUS  OR 
FLEXIBLE: 


For  all  metals   except  when  they  belong  to   Class  2. 


For  materials  fhat  are  to  be  melted  and  poured  into  place  hot,  and  that  set  solid  when  cool.  Babbitt 
metal  and  similar  alloys,  lead,  solder,  sulphur,  nvax,  paraffin  and  pitch  are  examples.  Materials  that 
are  to  be  softened  by  heat  and  squeezed  into  place  should  also  have  this  sectioning. 

This  will  generally  mean  some  kind  of  cement,   as  Portland  and  other  hydraulic  cements, 
plaster  of  Paris,  concrete,  mortar.    It  should  also  be  used  for  pastey  or  plastic  materials,  as  tallow, 
putty,  etc.  when  squeezed  into  place  without  being  heated. 

For  such  materials  as  leather,  leatheroid,  rawhide,  fibre,  asbestos,  felt,  rubber,  gutta-percha, 
ivory,  bone ,  etc. 


e:  WOOD: 


7:  STONE  CLASS: 


8:  LIQUID: 


9:  SPECIAL: 


It  is  often  desirable  to  imitate   the  grain  of  wood 
whether  in  section  or  not. 


This  sectioning  should  be  used  for  materials  that  belong  to  the  same  general  doss  as  stone.  Marble, 
Slate,  soapstone,  brick,  terra -cotfa,  porcelain  and  glass  are  examples. 


For  all  liquids  that  do  not  set  solid  at  ordinary  temperatures,  as  oil,  wafer,  alcohol,  glycerine, 


turpentine,  etc.. 


For  materials  that  are  entirely  special,   or  that  do  not  belong  to  one  of  the  above  classes. 


24 


FIG.  15.     STANDARD  SECTIONING  FOR  CLASSES  OF  MATERIALS. 


obtained  by  individual  sectionings  and  is  produced  with  decidedly  less 
trouble. 

72.  It  is  at  once  apparent  that  the  sectioning  for  a  given  individual 
material  will  not  always  be  the  same,  but  may  change  with  its  function 
or  with  the  method  of  preparing  it.     Thus,  a  separately  finished  piece 
of  babbitt  metal  will  have  sectioning  No.  i ;  the  same  material  poured 
intc  place  hoi  will  have  No.  2.     So  also  with  a  piece  of  fiber:  Used  as 
insulation  (whatever  other  function  it  may  fill)  it  will  have  sectioning 
No.  5;  used  mechanically — and  not  as  insulation — it  will  have  No.  4 
sectioning.     In  each  case  the  sectioning  points  definitely  to  the  class  of 
material,  not  to  the  material  itself. 

73.  If,  as  is  sometimes  the  case,  it  is  desirable  to  specify  the  individ- 
ual material  in  immediate  connection  with  the  surface  in  section,  it  is 
easily  done  by  writing  the  name  of  the  material  on  the  face  of  the  sec- 
tion, or  near  it — as  in  Fig.  16. 

74.  SECTIONAL  VIEWS. — The  grouping  of  sectional  views  is  governed 
by  the  laws  of  projection  as  stated  in  Chapter  IV,  and  needs  no  special 
comment. 

75.  When  there  is  a  set  of  sections  on  parallel  planes,  the  views  should 
be  arranged  in  the  reverse  order  of  the  planes;  and  the  cutting  lines 
should  be  so  lettered  that  the  views  will  fall  in  alphabetical  order  read- 
ing away  from  the  view  from  which  they  were  projected. 

76.  In  the  lettering  of  cutting  lines  the  planes  should  be  considered 
as  cutting  either  downward  or  from  left  to  right  and  the  lines  lettered 
accordingly.     Vertical  cutting  lines  will  then  be  lettered  AB,  CD,  etc., 
reading  downwards;  horizontal  ones,  AB,  CD,  etc.,  reading  from  left 
to  right;  and  if  inclined,  it  will  generally  be  easy  to  decide  whether  the 
line  should  be  considered  as  inclined  to  the  vertical  or  to  the  horizontal, 
and  this  will  determine  how  the  lettering  should  read. 


FIG.  16.     ILLUSTRATION  OF  EFFECT  OF  VARYING  WIDTHS  OF  SEC- 
TION  LINING  FOR  DIFFERENT  MATERIALS  OF  THE  SAME  CLASS. 


25 


77-  BROKEN  SECTIONS. — It  is  sometimes  desirable  to  make  a  single 
sectional  view  answer  the  purpose  of  two  or  more,  by  using  a  bent,  or 
"broken"  cutting  line  instead  of  a  true  cutting  plane.  This  kind  of 
section  is  best  indicated  by  the  use  of  an  additional  letter  at  each  bend 


or  break  in  the  cutting  line  and  should  always  be  lettered  in  this  man- 
ner, as  ABC,  instead  of  simply  AB;  this  will  distinguish  it  at  a  glance 
from  a  true  section,  and  will  make  the  drawing  just  so  much  easier  to 
read. 


CHAPTER  VI.     FINISHES    AND   THE    FINISH    MARK. 


78.  In  every-day  English  the  word  finish  means  "to  complete."     In 
workshops  the  same  word  has  several  other  meanings;  one  of  them — 
common  in  machine  shops — is  "to  shape  to  dimensions  with  a  cutting 
tool."     It  is  perhaps  unfortunate  that  custom  has  permitted  the  word 
to  be  used  in  this  special  sense,  but  it  cannot  be  helped;  and  it  is  not 
likely  that  anything  would  be  gained  by  an  attempt  to  introduce  a  new 
word  as  a  universal  substitute,  especially  as  Face,  Dress,  and  Shape  are 
already  used  in  some  shops  to  mean  the  same  thing.     It  is  probably 
best  to  accept  conditions  as  they  are,  and  agree  that  the  special  meaning 
of  the  word  shall  hold. 

79.  Broadly  speaking,  any  process  by  which  a  surface  is  completed 
is  a  finishing  process,  the  result  of  which  is  a  finished  surface — or  sim- 
ply a  "finish."     It  is  part  of  the  business  of  the  draftsman  to  say  what 
the  nature  of  a  finish  shall  be;  it  is  not  necessarily  his  business  to  state 
by  what  process  a  finish  shall  be  obtained,  but  it  is  essential  that  the 
drawing  shall  indicate  the  finish  itself — the  result. 

80.  In  this  there  is  a  principle  involved:  A  drawing  should  be  made 
right  to  stay  right;  which  means,  among  other  things,  that  it  should  as 


far  as  possible  allow  for  changes  in  shop  methods,  so  long  as  the  re- 
sults obtained  are  the  same.  There  is  an  application  of  this  principle 
in  Chapter  V,  paragraph  70:  "A  change  of  material  after  a  drawing 
has  been  made  does  not  necessitate  the  erasing  of  a  sectioning";  in 
other  words,  the  sectioning  is  made  right  to  stay  right. 

81.  In  the  matter  of  finishes  it  is  distinctly  poor  practice  for  a  draw. 
ing  to  say  how  a  result  shall  be  obtained;  for  example:  If  it  says  "plane," 
and  the  shop  "mills,"  the  drawing  is  wrong.     It  is  not  possible  to  say 
exactly  when  and  when  not  to  specify  a  finishing  process;  sometimes  it 
is  necessary,  but  on  principle  it  should  be  avoided,  because  unless  it  is 
agreed  that  a  change  of  process  shall  be  immediately  followed  by  a 
change  in  every  drawing  that  calls  for  the  superseded  process — which 
would  be  an  unbearable  hardship — drawings  are  liable  at  any  time  to 
become  ineffective  and  misleading. 

82.  The  finishes  that  it  is  necessary  to  specify  in  mechanical  drawings 
can  be  divided  into  two  general  classes:  (i)  Tool  finishes,  produced  by 
cutting  or  abrading.     (2)  Coat  finishes,  obtained  by  coating  with  some 
preservative. 


26 


83.  The  following  are  a  number  of  Tool  Finishes  with  their  defini- 
tions: 

FINISH. — Shape  to  dimensions  with  a  cutting  tool.  This  calls  for 
measured  adherence  to  dimensions  (either  within  limits  as  stated  on  the 
drawing,  or  as  considered  suitable  by  the  shop) ;  the  surface  to  be  such 
as  good  shop  practice  requires,  but  not  to  have  anything  done  upon  it 
for  mere  appearance. 

SPOT  FINISH. — Finish  a  circular  spot.  This  calls  for  measured  ad- 
herence to  dimensions,  and  can  be  done  with  a  counterbore  or  similar 
tool. 

SPOT  FACE. — Face  a  circular  spot.  This  does  not  call  for  measured 
adherence  to  dimensions;  otherwise  it  is  the  same  as  spot  finish. 

TRIM. — Shape  by  any  convenient  means;  as  by  chipping,  filing,  saw- 
ing, grinding,  etc.  This  does  not  call  for  measured  adherence  to  di- 
mensions. 

POLISH. — Make  the  surface  smooth  and  glossy.  Except  when  used 
in  conjunction  with  "Finish,"  this  does  not  call  for  measured  adherence 
to  dimensions  nor  for  a  perfectly  true  surface.  It  can  be  produced  by 
such  means  as  grinding  and  buffing. 

GRAIN. — Give  the  material  the  appearance  of  having  a  straight  grain; 
as  by  drawfiling  or  rubbing  with  emery  cloth. 

MATT. — Make  the  surface  artistically  rough.  This  can  be  done  by 
direct  hand  work  or,  in  the  case  of  a  casting,  by  covering  the  face  of  the 
pattern  with  pebble-surface  paper. 

84.  These  finishes  with  their  definitions  are  intended  to  relieve  the 
draftsman  of  responsibility  and  to  place  it  on  the  shop  where  it  rightly 
belongs.     An  example  will  show  what  this  means:  In  a  certain  estab- 
lishment, during  a  number  of  years,  several  hundred  drawings  were 
made  specifying  that  certain  holes  should  be  "drilled."     To-day,  by 


means  of  modern  tools  these  holes  are  accurately  punched;  and  now  the 
drawings  are  wrong  to  stay  wrong,  for  they  will  never  be  corrected;  it 
would  cost  too  much. 

85.  It  is  generally  no  affair  of  the  draftsman's — or  at  least  not  neces- 
sary for  the  drawing  to  state — whether  the  shop  will  plane,  mill,  shape, 
bore,  broach,  drill,  punch,  chip,  file,  saw,  grind,  scrape,  ream,  or  how  a 
result  will  be  obtained.  The  drawing  must,  however,  indicate  required 
results;  this  is  what  the  finishes  given  above  are  intended  to  do,  without 
limiting  the  shop  to  any  specified  processes.  The  judgment  of  the 


FIG.  17. 

draftsman  should  tell  him  when  it  is  necessary  or  wise  to  specify  an 
actual  process.  In  some  cases  the  name  of  the  finish  is  also  the  name 
of  the  process;  "Knurl"  is  an  example. 

86.  COAT  FINISHES. — A  great  number  and  variety  of  finishes  belong 
to  this  class;  as  paint,  lacquer,  varnish,  shellac,  French  polish,  Japan, 
electroplate,  oxidize,  boil  in  oil,  etc.     It  is  proper  to  designate  these  fin- 
ishes by  full  descriptive  name  or  by  some  well-understood  abbreviation 
of  it. 

87.  THE  FINISH  MARK. — In  drafting  rooms  it  is  common  practice 
to  mark  with  an  "f "  the  bounding  lines  of  surfaces  that  are  to  be  "fin- 
ished."    Unfortunately  this  "f,"  as  a  finish  mark,  easily  degenerates  into 
an  untidy  scrawl;  it  is  too  readily  scribbled,  and  when  applied  as  in 
Fig.  17 — which  is  an  example  from  an  existing  working  drawing — 
it  is  altogether  unsatisfactory. 


27 


THE    FINISH   MARK :    V*    Drawn  freehand.     Consists   of  a  thin,   straight  pointer  line,  with  two 
medium-weight   barbs   on   one_  side    of  the   line    and  a   circular   head   on  the   other  side. 
•SIZE :    The  standard  is  /f^_V*  but  this   should  be   varied  to  suit  the  character  of  the 
drawing   and  the  space   available. 

MANNER    OF  CONSTRUCTING".    First  draw  the  pointer  line;          /  /  /  / 

add   the  barbs;  finish   with   the  head.  CONSTRUCTION  IN  FOUR  STEPS 

ORDINARY  APPLICATION:  Apply   to   the  bounding  line  of  the 

surface  at  an  angle  of  3  in  8,  as  in   the  following   examples:       »'.g      \  t/          L         / 

The  barb  should  always  be  in  the  obtuse   angle  formed  by         —(-'.        "  "\       /  j*     /J 

the  pointer  line  and  the   line   of  surface,  never  thus :    % 

EXAMPLES    OF  APPLICATION 

SPECIAL  APPLICATION.'  When  a  surface  is  of  such  a  shape  as  to  naturally  require  several 
finish  marks  inconveniently  close  together,  indicate  the  extent  of  the  finish  by  using  two 
marks  as  dimension  arrow-heads,  thus: 

I  l  l — r-i — I  \ J       This  means  that  the  entire  surface  between  the  projection 

lines  is  to  be  finished.    Compare  this   with  Fig.  17. 

CONJUNCTIONS'  Sometimes   it  is  necessary  to  specify  a  double  finish, as  Finish  and 
Polish  '.'   The  mark  can  then  be  used  in  conjunction,   thus : 

Spo/ish  /  Grain  ^Scrape 

//  /5  often  advisable   to  specify  a  finish  by  means  of  a  note,  as  Finish  all  over:    Trim  flush 
with  edge  of  flange:    Finish   and  Polish  from  A    to  B:    Polish  exposed  surfaces :  Grain 
parallel  to  edge  CD. 

FIG.  18.     THE  FINISH  MARK. 
28 


88.  The  finish  mark  presented  in  Fig.  18  was  the  outcome,  some  five 
years  ago,  of  an  effort  to  find  something  better  than  the  "f."  It  pos- 
sesses the  advantage  of  pointing  to  the  line  instead  of  cutting  it;  it  has 


a  distinct  individuality  and  is  very  visible,  it  is  easy  to  draw  but  diffi- 
cult to  scribble,  and  the  special  application  of  it  for  broken  surfaces  is 
decidedlv  valuable. 


CHAPTER   VII.     DIMENSIONING. 


89.  In  attempting  to  lay  down  the  general  principles  upon  which  a 
study  of  mechanical  drawing  should  depend,  I  said,  in  Chapter  I., 
that  mechanical  drawing  is  a  language. 

90.  Now,  the  writing  of  a  language  may  be  for  a  variety  of  purposes. 
The  English  language,  for  example,  is  used  in  an  almost  endless  vari- 
ety of  ways,  to  obtain  an  almost  endless  variety  of  results;  from  the 
speaking  of  a  simple  sentence,  resulting  in  the  making  known  to  another 
person  of  a  simple  fact,  to  the  written  expression  of  a  scientific  theory, 
based  upon  a  multitude  of  facts,  and  resulting  in  the  printed  reference 
book  for  the  benefit  of  many  people. 

91.  For  the  guidance  of  those  who  use  our  language,  comprehensive 
dictionaries  and  encyclopedias  have  been  compiled,  and  a  recognized 
science  called  grammar  deduced;  so  that  no  matter  what  the  result  of 
writing  the  language  may  be,  whether  it  be  a  reference  book  or  a  mag- 
azine story,  an  engineering  specification  or  an  advertising  pamphlet,  a 
railroad  ticket  or  a  theater  poster,  the  same  alphabet  and  words  are  em- 
ployed, with  the  same  methods  of  sentence  construction.     But  this  sim- 
ilarity of  language  does  not  prevent  us  from  easily  distinguishing  a  rail- 
road ticket  from  a  theater  poster,  or  a  reference  book  from  a  magazine 


story;  because  each  is  built  on  its  own  lines  for  its  own  purposes.  And 
it  would  be  quite  useless  to  try  to  formulate  special  rules  for  the  prep- 
aration of  one  that  would  be  of  any  practical  assistance  in  the  prepara- 
tion of  any  other. 

92.  It  is  much  the  same  with  this  language  of  lines,  for  there  are  many 
kinds  of  mechanical  drawings;  and  before  any  attempt  can  be  made  to 
deal  intelligently  with  the  subject  of  dimensioning  it  will  be  necessary 
to  arrive  at  a  concise  and  comprehensive  definition  of  the  particular 
kind  of  mechanical  drawing  that  this  dictionary  is  intended  to  govern. 

93.  If  the  sole  purpose  of  a  drawing  be  to  discover  some  unknown 
dimension,  it  is  generally  called  a  "layout."    With  the  discovery  of  the 
dimension  such  a  drawing  has  played  its  part;  its  work  is  finished. 
Similarly,  if  its  purpose  be  to  determine  the  contour  of  a  cam,  it  serves 
its  purpose  and  may  be  destroyed.     Again  a  mechanical  drawing  may 
be  in  the  nature  of  a  thesis — an  essay  in  lines,  as  it  were;  or  it  may  be 
intended  solely  for  descriptive  or  illustrative  purposes. 

94.  So  far  as  the  language  itself  is  concerned  certain  grammatical 
rules,  as  those  governing  projection  and  the  meaning  of  the  dimension 
line,  must  always  hold;  but  there  are  many  rules,  among  which  are 


29 


SECTION  A 8 




SECTION  JK'' 


SECTION  GH 

THC  DOVETAIL.  Fun  *zt 
FIG.  19.     CAST-IRON  ARMATURE  SPIDER. 


30 


those  that  govern  dimensioning,  whose  application  will  depend  to  a 
large  extent  upon  the  kind  of  drawing  required  and  the  uses  to  which 
it  will  be  put. 

95.  When  a  mechanical  drawing  illustrates  the  shape  and  construction 
of  something  that  is  to  be  made,  and  specifies  the  required  product — as  by 
giving  dimensions,  material,  finish,  and  quantity  required — {/  is  in  effect 
an  illustrated  specification.     This  is  the  particular  kind  of  drawing  that 
we  are  interested  in  here  and  that  this  dictionary  is  intended  to  govern 
— the  "illustrated  specification,"  for  the  use  of  shop,  office,  and  draft- 
ing room,  to  be  referred  to  again  and  again  by  those  concerned  in  the 
manufacture,  sale,  or  design  of  the  specified  product. 

96.  In  relation  to  such  a  drawing,  the  definition  given  in  Chapter  I. — 
that  "mechanical  drawing  is  a  language  of  lines,  views,  dimensions, 
signs  and  abbreviations,  notes  and  explanatory  matter,  all  for  the  pos- 
itive conveying  of  exact  information" — has  an  interesting  significance, 
for  we  may  at  once  divide  the  drawing  into  three  simple  elements — 
illustration,  dimensions,  and  written  matter. 

97.  In  composing  such  a  drawing,  the  problem  is  how  to  distribute 
these  elements  so  that  each  may  play  its  part  to  the  best  advantage. 

98.  Taking  first  the  illustration — the  projected  view  or  views — the 
primary  purpose  is,  of  course,  to  show  a  required  shape  or  design;  but 
this  is  not  always  the  most  valuable  purpose  finally.     In  every  drawing 
the  illustration  is  made  to  serve  as  a  "vehicle"  for  the  dimensions,  and 
very  often  it  is  eventually  of  more  value  in  this  capacity  than  as  a  "shape." 
Take,  for  example,  the  illustration  of  the  cast-iron  armature  spider  in 
Fig.  19.     After  the  pattern  has  been  made,  the  drawing  is  referred  to 
in  the  shop,  not  to  discover  the  shape  of  the  casting,  because  the  pat- 
tern has  fixed  that  and  the  casting  is  there,  but  for  the  dimensions  and 
written  matter. 


99.  It  behooves  the  draftsman  occasionally  to  remind  himself  of  the 
fact  that  the  man  in  the  shop  has  the  drawing  in  one  hand  and  the 
piece  in  the  other,  and  is  looking  to  the  drawing  for  a  dimension  that 
he  needs  and  has  a  right  to  expect;  that  if  it  is  not  given  he  has  a  right  to 
complain,  and  that  the  illustration — as  a  "vehicle" — should  carry  the 
dimension  naturally,  where  it  can  be  easily  found  and  easily  read,  and, 
if  possible,  where  the  man  in  the  shop  will  naturally  look  for  it. 

100.  Dimensioning  may  therefore  be  defined  as  the  art  of  determining 
•what  dimensions  are  required,  and  of  applying  them  correctly  to  the  lines 
and  views  of  a  drawing. 

101.  REQUIRED  DIMENSIONS. — It  often  happens  that  the  dimensions 
used  by  the  draftsman  as  he  develops  a  design  would  not  be  convenient 
as  working  dimensions  for  the  shop.     In  other  words,  the  dimensions 
required  by  the  shop  are  not  always  the  same  as  those  used  in  the 
drafting  room.     The  shop  requirements  generally  depend  upon  the 
way  in  which  the  work  will  be  done — the  manner  in  which  measure- 
ments will  be  made  and  the  order  in  which  surfaces  will  be  finished. 
Fig.  20  shows  two  dimensionings  of  a  part  of  the  casting  illustrated  in 
Fig.  19;  at  a  the  dimensions  are  numbered  in  the  order  in  which  the 
surfaces  will  be  finished.     Dimensioned  as  at  b,  the  shop  would  have 
to  add  A,  B,  and  C  together  to  get  No.  i,  B  and  C  to  get  No.  2,  and 
would  not  need  A  at  all. 

102.  This  leads  to  a  statement  of  the  first  principle  to  be  observed — 
dimensions  should  be  so  given  that  the  shop  "will  not  have  to  add  or  sub- 
tract in  order  to  discover  required  distances.     This  is  only  another  way 
of  saying  "give  the  dimensions  that  the  shop  requires,"  except  that  it 
points  clearly  to  the  necessity  of  not  being  satisfied  unless  the  dimen- 
sions are  individually  what  the  shop  will  want  to  use.     Such  dimen- 
sioning calls  for  a  greater  knowledge  of  shop  methods  than  the  average 


31 


draftsman  of  to-day  possesses;  also  for  more  thought  than  he  usually 
gives  to  the  subject;  but  it  would  go  a  long  way  toward  removing  that 
prejudice  between  drafting  room  and  shop  which  we  have  come  to 
look  upon  as  almost  a  necessary  evil. 

103.  So  far  we  have  spoken  of  the  "shop"  as  though  it  were  a  unit; 
in  reality  the  engineering  shop  consists  of  several  more  or  less  inde- 


are  the  dimensions  required  by  the  machinist, 
'  numturta1  in    the  order  in  which  he  will  usf  them. 


AB 

•^ 


Ut 


I  b:  This  dimensioning   would  cause  tnfublt  in  tht  shop 


Fie.  20. 


worth  while  to  consider  the  shop  requirements  and  the  nature  of  the 
work  to  be  done. 

104.  As  a  rule,  the  working  or  finish  dimensions— those  required  by 
the  machine  shop — have  the  greatest  value,  and  will  rank  first  in  im- 
portance, because  they  directly  guide  and  control  work  done  on  raw 
material  and  have  to  play  an  active  part  during  the  entire  life  of  the 


This  is  an  example  of  "cent  r  line" 'dimension 'na,  such  as 
draftsmen   have   been   known   to  send  to  the   $h< 

Fie,.  2V. 


FIGS.  20  AND  21.     EXAMPLES  OF  METHODS  OF  DIMENSIONING. 

(  Both  ;tre  ]>:ised  on  a  part  of  Ihc  casting  shewn  in  Fig.  19.) 


pendent  workshops,  as  pattern  shop,  foundry,  machine  shop,  etc.  Now, 
it  is  often  necessary  to  bear  in  mind  that  the  dimensions  required  i>y 
the  different  workshops  may  differ  widely  from  one  another,  both  in 
character  and  value.  Thus,  when  the  drawing  represents  a  casting, 
as  does  Fig.  19,  some  of  the  dimensions  will  be  especially  for  the  pat- 
tern shop,  others  for  the  machine  shop,  some  for  both.  It  is  always 


32 


drawing  (see  Paragraph  35,  Chapter  III.).  The  dimensions  for  the  pat- 
tern shop  are  generally  of  lea>t  "final  value,"  not  because  they  are  any 
less  important  originally,  but  because,  after  the  pattern  has  once  been 
made,  they  are  seldom  used.  In  some  drafting  rooms  special  draw- 
ings are  made  for  the  pattern  maker,  carrying  his  dimi'n>ions  only, 
the  "working"  drawings  being  thus  relieved  of  their  burden. 


FIG.  F3. 

FIGS.  22  AND  23.     GOOD  DIMENSIONING  FOR   FLANGE  COUPLING,  WITH    KEY  TO  SAME. 

Key  to  the  Dimensioning  in  Fig.  22  (see  Fig.  23). 

The  following  is  intended  to  show  that  there  is  often  a  reason  why  a  dimension  should  l>e  applied  in  one  place  rather  than  another.     The  reasons  are  given,  not  because  there  is  anything  final  or  definite 
about  them,  but  to  suggest  a  line  of  thought,  and  to  show  that  there  is  such  a  thing  as  intelligent  dimensioning. 

A:  The  bore  will  be  measured  from  the  end. 

B:  This  center  line  circle  will  be  laid  out  on  the  end. 

C  and  D:  The  dimensions  are  applied  as  the  diameters  will  be  calipered. 

E,  F,  G  and  H:  These  external  dimensions  arc  placed  outside  the  view. 

J  and  K:  These  internal  dimensions  are  placed  inside  the  view. 

L:  This  diameter  is  placed  as  it  will  Ix:  calipered,  and  to  the  right  because  the  part  referred  to  points  in  that  direction. 

M  and  X:  Each  of  these  dimensions  is  placed  on  the  half  of  the  coupling  to  which  it  Ix'longs. 

P,  Q,  R  and  S.  Grouping  the  radius  dimensicns  in  this  manner  is  better  than  scattering  them,  and  there  is  clear  room  for  them  on  this  side  of  the  view.  S3 


THE  POINTER: 


Consisting  of  thin  pointer  line  of  suitable  shape,    with  a 
single-barb  head     The  barb  should  always  be  placed  on 
the   more   open  side   of   the  pointer  line,  thus   \^~ '    never   ^^ 

In    general  the  Pointer  is  for  definitely  connecting  a  note  or  dimension   with  some  part  of  the 
drawing     The  barb   should  always   touch  the  part  referred  to. 


THE  INDICATOR-. 


Consisting  of  a  short,   medium-  weight  direction  line   with  a  small  circle  at  one  end. 

This   sign  is  shown  to   advantage  in  Fig.  19  where  it 
serves  as  an  indicator   between  the  sectional   views  and  their  respective   cutting  lines.     The  "indicator* also 
forms  a  part  of  the  "substitute  for  a  repeat  dimension";  see  Fig.  3f. 


THE  ARROW-. 


Consisting  of  thin  direction   line,    shaded  feather,   and  a 
double -barb  head. 


In   general  the  arrow  is  for  indicating  direction  of  motion  or  force. 


FIG.  24-.    SIGNS   OF  DIRECTION. 


DIAMETERS  and  RADII :  The  following  example  dfmensionings  of  diameters  and  radii  are  intended  to 
show  that  no  matter  what  the  surroundings  of  a  circle  or  arc  may  be,  it  is  generally  possible  so 
to  apply  the  dimension  that  the  drawing  will  be  easy  to  read  and  good  fo  look  at.  „ 

In   example  A   it  is    made  clear  that  the ,,72 £  /s  a  diameter,    and  in  B.  that  the  /Jy  is  a  radius. 
The   abbreviations  "dia"  for  diameter,    and  "R"  for  radius   should  be    used  in    this    way    whenever 
there    could   otherwise  be  a    doubt  as   to  the  meaning  of  a   dimension;   but  when  the   meaning 
is   evident   the  dimension   alone  is  sufficient. 


FIG  25.     THE.  APPLICATION  OF  DIMENSIONS 
FIGS.  24  AND  25.    SIGNS  OF  DIRECTION  AND  THE  APPLICATION  OF  DIMENSIONS. 

34 


105.  In  Fig.  21  is  an  example  of  "center  line  dimensioning,"  such  as 
draftsmen  have  been  known  to  send  to  the  shop.     While  these  dimen- 
sions are  often  of  value  to  the  draftsman  when  laying  out  a  design,  and 
may  be  useful  also  to  the  pattern  maker,  they  are  seldom  of  much  value 
to  the  machine  shop,  especially  if  the  center  line  happens  to  be  entirely 
"atmospheric."     Fig.    22   exhibits  a  good  dimensioning   of  a    rlange 
coupling.     Fig.  23  is  in  the  nature  of  a  "key"  to  this  dimensioning,  with 
explanatory  notes. 

106.  Before  passing  to  a  consideration  of  the  application  of  dimen- 
sions, the  reader's  attention  is  directed  to  the  three  Signs  of  Direction 
in  Fig.  24.     The  "pointer"  there  shown  deserves  a  word  or  two.     Its 


2: 


H 

IHHT  IN-*' 
"H  --  +*'• 


-«# 


FIG.  26.     SIX  DIMENSION  CONSTRUCTIONS. 

purposes  are  stated,  and  in  Fig.  25  several  applications  are  illustrated. 
The  main  feature  of  it  is  the  single-barb  head,  by  which  -it  is  easily  dis- 
tinguished from  the  end  of  a  dimension  line.  The  single  barb  also  en- 
hances its  efficiency  as  a  clear  and  definite  pointer.  Its  uses  should 
not  be  confused  with  those  of  the  Indicator  or  the  Arrow. 


107.  THE  APPLICATION  OF  DIMENSIONS.— In  Chapter  III.  six  "dimen 
sion  constructions"  were  given.     For  convenience,  they  are  repeated 
here  in  Fig.  26.     The  purpose  of  these  constructions  is  to  make  it  im- 
possible for  a  dimension  to  be  misunderstood.     Fig.  25  shows  them  ap- 


(b) 


FIG.    27..   WRONG    AND     RIGHT     WAY    OF    INDICATING     RADIUS    OF 
ROUNDED  CORNER. 

plied  to  circles  and  circular  arcs — diameters  and  radii.  In  the  work 
of  the  average  draftsman  it  is  not  at  all  uncommon  to  find  the  radius 
of  a  rounded  corner  given  as  at  (a)  Fig.  27.  The  arrangement  shown 
at  (6)  is  much  simpler — so  simple,  indeed,  that  draftsmen  have  been 
known  to  object,  on  the  ground  that  it  is  in  some  way  ambiguous;  yet 
there  can  hardly  be  any  doubt  as  to  its  meaning;  it  is,  in  fact,  a  perfectly 
rational  way  of  indicating  such  a  radius.  It  is  seldom  necessary  actu- 
ally to  mark  the  center  of  a  rounded  corner  or  fillet,  because  the  po- 
sition of  the  center  itself  is  of  no  practical  value  to  anyone;  what  the 
drawing  should  give  is  the  nature  of  the  curve,  and  this  is  done  com- 
pletely by  specifying  the  radius  length.  In  (a)  the  draftsman  has  used 
a  pointer  of  absurd  shape;  that  is  what  it  really  amounts  to. 

108.  Fig.  28  shows  how  dimensions  may  be  applied  to  a  drawing  of 
a  shaft.  The  view  has  been  made  to  serve  efficiently  as  a  vehicle  for 
the  required  dimensions;  it  is  best  to  put  the  bulk  of  the  dimensions 
above  the  view,  because  when  the  shaft  is  in  the  lathe  it  is  only  the  up- 


3.5 


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//»   A/7«   drawing    the   illustration  has  fatn  made  to  serve 

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FlG, 29 :   Reproduced  from  on  actual    working  drawing;  showing  how  not  to  dimansion  a  shaft.    Compare   with  Fig.2£. 
FIGS.  28  AND  29.     RIGHT  AND  WRONG  METHODS  OF  DIMENSIONING  A  DRAWING  OF  A  SHAFT. 


per  half  of  it  that  is  visible;  and  it  is  reasonable  to  put  the  bearing  center 
distances  below  the  view,  because  in  the  complete  machine  the  bear- 
ings will  be  under  the  shaft.  Fig.  29  is  reproduced  from  a  drawing 
made  by  a  draftsman  who  did  not  know  how  to  dimension  this  shaft. 
Dimensions  that  are  thus  thoughtlessly  applied  are  almost  always  diffi- 
cult to  find,  which  means  that  time  is  lost  and  somebody's  patience 
tried  whenever  the  drawing  is  referred  to.  It  is  not  right  that  a  ma- 
chinist should  be  put  to  unnecessary  trouble  in  order  to  read  a  draw- 
ing; he  will  do  more  and  better  work  from  a  drawing  that  is  easy  to 
read  than  from  one  that  has  to  be  translated. 

109.  It  will  be  noticed  that  in  these  drawings  the  dimension  figure  is 
occasionally  placed  as  illustrated  separately  in  Fig.  30.  This  is  not  a 
new  arrangement.  It  is,  however,  so  useful  and  so  little  used  that 
something  should  be  said  about  it.  When  the  placing  of  the  figure 
across  the  dimension  line  will  make  the  drawing  easier  to  read,  it  is 
best  to  place  it  so,  because  drawings  are  made  to  be  read.  It  is  true  that 


FIG.    30.     AN    OCCASIONALLY    USEFUL    WAY    OF    FIGURING    A 
DIMENSION. 

generally  the  figure  may  lie  -with  the  dimension  line,  but  when  some 
other  arrangement  would  be  more  readable  it  should  be  used;  cer- 
tainly tradition  should  not  be  allowed  to  stand  in  the  way.  In  our 
every-day  work  we  are  all  more  or  less  slaves  to  tradition;  a  little  flex- 
ibility is  a  good  thing,  and  will  often  help  the  draftsman  out  of  a  tight 
place. 


no.  It  would  not  be  difficult  to  find  grounds  for  advocating  a  more 
general  use  of  the  arrangement  just  referred  to.  In  Fig.  22  all  the  di- 
mensions are  so  arranged,  and  are  certainly  very  easy  to  read.  How- 
ever, it  would  not  be  wise  to  altogether  abandon  the  older  method; 
it  is  probably  better  to  use  both,  each  where  it  seems  right;  though, 
after  all,  this  is  a  matter  rather  of  style  than  anything  else,  and  does 


37 


FIG.  31.     A  SUBSTITUTE  FOR  REPEATING  A  DIMENSION. 

not  affect  any  principle.  Fig.  31  contains  a  suggested  substitute  for 
repeating  a  dimension.  The  greatest  objection  to  repeating  arises  when 
a  change  is  to  be  made;  then,  if  by  any  chance  a  "repeat"  is  left  un- 
changed, trouble  may  ensue.  This  special  application  of  the  Indicator 
is  suggested,  not  because  any  general  use  of  it  is  recommended,  but  in 
order  that  the  draftsman  may  have  such  a  device  at  his  command:  it 
sometimes  helps. 

in.  It  is  impossible  to  lay  down  hard-and-fast  rules  for  applying 
dimensions,  because  we  are  not  dealing  with  an  exact  science,  but  the 
following  may  be  taken  as  in  a  general  way  summing  up  the  require- 
ments: 

(1)  The  illustration  should  be  made  to  serve  efficiently  as  a  "vehi- 
cle," carrying  the  dimensions  naturally;  that  is,  with  due  regard  to  the 
manner  in  which  the  work  will  be  handled  in  the  shop,  or  the  dimen- 
sions used  elsewhere. 

(2)  Every  dimension  should  be  placed  where  there  is  clear  room  for 
it,  and  the  construction  chosen  to  suit  the  lines  of  the  drawing  and  the 
space  at  disposal. 


(3)  Dimensions  for  one  workshop  should  not  be  indiscriminately 
mixed  with  those  for  another. 

(4)  A  dimension  should  not  be  repeated  unless  doing  so  will  in  some 
way  make  the  drawing  easier  to  understand. 

112.  Assuming  sufficient  knowledge  and  experience,  a  little  intelli- 
gent thinking  will  enable  the  draftsman  to  meet  these  requirements; 
not  in  every  detail,  and  not  in  such  a  manner  as  to  defy  criticism,  but 
certainly  to  an  extent  that  will  repay  for  the  effort  required.    The  di- 
mensionings  given   of  the   spider,  the   shaft,  and   the   coupling  were 
worked  out  with  considerable  care,  and  are  actual,  not  imaginary,  ex- 
amples, being  reproduced  with  very  few  changes  from  working  draw- 
ings made  some  years  ago.    It  is  hoped  that  they  will  be  of  some  as- 
sistance to  the  student  of  this  interesting  language,  by  showing  him 
that  by  simple  means  it  is  possible  to  make  drawings  that  are  in  every 
way  a  pleasure  to  read. 

1 13.  Not  many  years  ago  the  writer  knew  a  young  man  who  entered 
the  employ  of  a  large  engineering  concern  as  "tracer."    He  had  previ- 
ously been  a  salesman  in  a  dry  goods  store,  but  was  ambitious,  and  un- 
der the  coaching  of  a  friend  had  acquired  some  dexterity  in  the  handling 
of  drafting  instruments,  notably  the  tracing  tools.     He  was  naturally 
a  good  penman,  and  was  soon  able  to  make  tracings  that  passed  mus- 
ter; and,  being  industrious,  he  finally  became  quite  "expert,"  turning 
out  neat  work  rapidly.     By  and  by  he  was  promoted  to  a  position  at 
the  drawing  board  and  was  permitted  to  make  detail  drawings  in  pen- 
cil, and  even  to  "dimension"  them;  in  fact,  was  duly  enrolled  in  the 
ranks  as  draftsman.     In  other  words,  this  man,  who  had  scarcely  seen 
the  inside  of  a  machine  shop,  and  actually  did  not  know  a  lathe  from 
a  radial  drill,  was  paid  so  much  an  hour  for  preparing  "illustrated  spec- 
ifications" for  the  use  of  the  shop. 


114.  In  the  face  of  this  as  a  fact,  is  it  surprising  that  there  is  some 
misunderstanding  as  to  the  real  significance  of  the  term  draftsman,  and 
some  doubt  as  to  his  rank  in  the  engineering  professions?    His  cry  for 
professional  recognition  is  not  without  reason,  but  it  can  be  of  little 
or  no  avail  until  he  is  able,  without  supervision,  to  do  his  work  as  it 
should  be  done. 

115.  It  is  perhaps  not  too  much  to  say  that  the  successful  draftsman 
of  the  future  must  be  first  of  all  an  engineer,  and  then  that  his  am- 
bition must  be  not  to  get  away  from  the  board,  but  to  develop  his  pow- 
ers at  the  board,  so  that  he  may  do  better  designing  and  make  more 
efficient  drawings  of  every  kind.     Of  course,  so  long  as  the  really  efli- 
cient  draftsman  is  as  rare  as  he  is  to-day,  he  will  continue  to  be  called 
upon  to  assist  the  rank  and  file,  and  it  will  continue  to  be  necessary,  for 
economic  reasons,  to  use  him  as  a  chief  draftsman  or  foreman  and  to 
have  working  under  him  the  draftsman  of  smaller  caliber,  whose  duty 
it  will  continue  to  be  to  receive  instructions,  obey  orders,  and  work 
under  constant  supervision  in  all  matters  pertaining  to  the  drawing  as 
the  writing  of  a  language  and  as  a  "tool"  for  the  use  of  the  shop.    And 
so  long  as  our  educational  institutions  separate  mechanical  drawing  as 
a  study  from  designing,  the  language  from  the  writing  and  use  of  it, 
and  graduate  men  who  look  with  contempt  upon  the  making  of  mere 
drawings,  and  consider  any  time  they  may  have  to  spend  at  the  board 
as  an  irksome  preliminary  to  their  advent  as  "engineers,"  so  long  will 
the  graduate  neglect  to  study  drawing  as  it  should  be  studied. 

116.  It  seems  as  though  the  average  draftsman  of  to-day  is  either 
not  a  student  at  all  or  is  a  student  of  something  else  than  drafting: 
either  unconsciously  willing  to  go  to  seed  as  a  "draftsman  pure  and 
simple"  or  ambitious  to  get  away  from  the  board  altogether  and  be 
something  other  than  draftsman,   though  just  what   that  something 


might  be  he  would  often  be  puzzled  to  state.  Far  too  many  draftsmen 
are  only  theoretically  ambitious,  and  neglect  to  see  in  their  own  work 
the  direct  road  to  success;  it  is  their  attitude  toward  their  work  that  is 
at  fault. 

117.  There  is  to-day  a  great  field  in  the  world  of  engineering  for  the 
really  efficient  draftsman:  the  one  who  loves  his  work  at  the  board,  who 
feels  that  drafting  is  a  profession  to  be  proud  of,  and  who  has  made 
and  continues  to  make  a  systematic  study  of  the  many  branches  of  en- 
gineering that  find  expression  in  his  work. 

118.  In  the  first  place,  he  should  be  able  without  extraordinary  ef- 
fort to  make  an  absolutely  accurate  layout;  should  be  familiar  with  the 
principles  of  geometry  and  able  to  solve  such  mathematical  problems 
as  may  present  themselves.     He  should  be  well  grounded    in  physics 
and  broadly  and  intimately  familiar  with  the  elements  of  machine  de- 
sign; notably,  perhaps,  every  known  form  of  fastener,  bearing,    and 


means  of  transmitting  motion  and  power;  also  of  such  mechanical  con- 
trivances as  are  most  commonly  used  in  machinery.  He  should  be 
able  to  make  a  reasonably  good  free-hand  sketch,  and,  not  by  any 
means  of  least  importance,  he  should  be  able  to  make  a  vivid  mental 
picture  of  what  he  draws,  and  see  in  detail  the  results  that  will  finally 
ensue  in  the  shop.  Outside  of  all  this,  he  should  have  a  clear  concep- 
tion of  the  business  relations  of  the  drawing  with  the  shop  and  other 
departments.  He  must  also  keep  abreast  of  the  times  in  matters  re- 
lating to  shop  practice,  processes  of  manufacture,  and  shop  and  office 
systems. 

1 19.  Nothing  less  than  this  will  enable  him  to  handle  the  language 
efficiently  or  to  find  lasting  pleasure  in  his  work.  And  possessing  such 
knowledge,  he  will  no  longer  have  to  spend  his  every  working  hour 
doubled  up  like  a  half-closed  jackknife  over  the  edge  of  a  pine  board,  but 
will  find  extended  to  him  a  pleasurable  and  profitable  variety  of  work. 


CHAPTER   VIII.      THE    RECORD    STRIP. 


120.  A  mechanical   drawing — by  which   is  meant   the   "illustrated 
specification,"  as  defined  in  Chapter  VII.,  paragraph  95 — is  not  com- 
plete until  it  has  been  titled  and  numbered. 

121.  In  drafting  rooms  the  world  over  it  has  long  been  customary  to 
allow  the  title  to  include,  in  addition  to  a  description  of  the  contents  of 
the  drawing,  the  name  and  address  of  the  firm;  and  also  to  have  it  carry 


the  drawing  number,  the  scale  of  the  work,  the  signatures  of  those  who 
shared  in  making  the  drawing,  and  the  date  of  completion. 

122.  A  generation  ago  draftsmen  were  permitted  to  elaborate  these 
titles  by  the  use  of  ornamental  lettering  and  other  more  or  less  artistic 
embellishment;  in  fact,  the  title  was  often  a  very  conspicuous  feature, 
being  executed  according  to  the  individual  taste  of  the  draftsman,  who 


would  appear  to  have  had  more  spare  time  than  he  knew  what  to  do 
with.  Such  a  title,  made  about  thirty-five  years  ago,  is  shown  in  Fig. 
32.  It  occupied  the  lower  right-hand  part  of  the  drawing,  and  covered 
fully  one-eighth  of  the  entire  sheet. 

123.  The  form  of  title  used  to-day  by  a  modern  firm  of  machine  tool 
builders  is  shown  in  Fig.  33.     In  this,  neatness  and  uniformity  are  as- 
sured by  having  those  parts  that  are  common  to  all  titles  press-printed 
in  the  lower  right-hand  corner  of  the  sheet,  ready  for  the  draftsman  to 
fill  in.     This  title  has  an  official  appearance  entirely  lacking  in  Fig. 
32;  it  also  carries  records  of  changes  and  other  data  of  value. 

124.  These  may  be  taken  as  typical  examples  of  titles  ancient  and 
modern.    At  first  sight  they  appear  to  offer  a  great  contrast;  but  it  is 
almost  at  once  evident  that  they  differ  in  appearance  and  design  rather 
than  in  general  character,  although  the  one  does  carry  certain  record 
data  not  found  in  the  other.    A  serious  fault  common  to  both — and 
common  to  titles  in  general  to-day — is  that  they  are  designed  to  occupy 
the  lower  right-hand  corner  of  the  drawing,  thus  rendering  a  valuable 
part  of  the  sheet  permanently  unavailable  for  drawing  on,  whether  con- 
venient or  not;  and  another  fault — also  common  to  titles  in  general — 
is  that  they  are  collections  of  dissimilar  items. 

125.  There  is  no  valid  reason  why  the  name  and  address  of  a  firm, 
the  number  and  scale  of  a  drawing  and  the  place  where  it  is  filed,  the 
dated  signatures  of  several  draftsmen,  sundry  order  numbers,  data  re- 
garding changes  and  pieces  affected,  and  a  description  of  the  contents 
of  a  drawing,  should  be  crowded  together  into  a  kind  of  potpourri  de- 
sign and  christened  "title."    It  is  an  attempt  to  mix  things  that  should 
be  separated — probably  the  result  of  conservatism,  that  unconscious 
tendency  in  drafting  rooms  to  stand  by  old  traditions. 

126.  Fig.  34  shows  what  can  be  done  by  systematically  distributing 


these  items  as  "record  data"  over  a  narrow  strip  extending  across  the 
entire  foot  of  the  drawing.  By  this  arrangement  a  clear  rectangle  is 
always  available  for  drawing  on,  which  is  as  it  should  be;  and  the  rec- 
ord strip  affords  ample  space  for  all  necessary  records.  The  exact 
nature  of  these  records — in  other  words,  the  contents  of  the  record  strip 
— cannot  be  defined  in  such  a  way  as  to  fully  meet  the  varied  require- 
ments of  all  drafting  rooms,  but  the  following  will  serve  as  an  example 
of  what  the  contents  may  be,  to  be  modified  according  to  the  conditions 
existing  in  any  particular  drafting  room: 

(1)  Firm  name  and  address. 

(2)  Title — descriptive  of  the  contents  of  the  drawing. 

(3)  Drawing  number. 

(4)  Scale. 

(5)  Dated  signatures  of  those  who  took  part  in  the 

making  of  the  drawing. 

(6)  Dated  O.  K.  signature  of  the  person,  generally 

the  chief  draftsman,  who  is  officially  and  finally 
responsible  for  the  drawing. 

(7)  Sub-numbers. 

(8)  First  order  number,  or  its  equivalent,  in  connec- 

tion with  which  the  drawing,  as  defined  by 
each  sub-number,  is  used. 

(9)  Records  of  changes  for  which  new  sub-numbers 

were  given. 

127.  Of  these  items  the  first  six  do  not  call  for  special  comment;  the 
last  three  do,  because  they  directly  influence  the  permanent  and  uninter- 
rupted efficiency  of  every  drawing  after  it  has  once  been  changed  jrom 
the  condition  in  which  it  was  originally  used',  and  there  are  compara- 


40 


v. .--... tl-- 

O-   THF 

UNIVERSITY 


lively  few  drawings  made  that  do  not  require  changing  at  one  time  or 
another. 

128.  One  of  the  most  prolific  sources  of  trouble  in  the  modern  draft- 
ing room  and  shop  is  this  changing  of  drawings;  especially  when  the 


change  and  filed  away  for  future  reference,  but  it  would  be  out  of  place 
to  enter  into  any  consideration  of  them  here.  Whatever  system  is  used, 
the  drawing  itself — the  tracing — should  carry  some  record  of  every 
change,  even  though  it  be  no  more  than  the  date  of  the  change,  with  a 


Engineers. 

AGRICULTURAL  &  HORTICULTURAL  MACHINERY. 
= MANCHESTER,   ENGLAND- 


GORTON  LAWN  MOWER 

SIDE   ELEVATION. 


Drawn 


FIG.  32.      REPRODUCTION   OF  TITLE  OF  AN  OLD  DRAWING. 

change  affects  a  piece  that  has  to  be  supplied  for  repairing  a  machine 
built  prior  to  the  making  of  the  change.  In  such  a  case,  if  there  is  any 
doubt  as  to  what  the  drawing  specified  before  the  change  was  made, 
annoying  troubles  are  almost  sure  to  follow. 

129.  There  are  many  ways  in  which  drafting  rooms  take  care  of 
such  changes,  as  by  the  use  of  special  record  prints  made  prior  to  the 


30    MOTOR- DRIVEN  LATHE 

General    Assembly 

THE  LODGE  &  SHIPLEY    MACHINE!  TOOL  COMPANY 
CINCINNATI,  OHIO. 


ORIGIN  <$&  <2l*tvr*/ 

PLUC\LtQ&?(&&at 

TRACED  /1tM*«AL*s 

FIRST   LOT  NO.  tlt>l& 

FIRST  SHOP  NO.   6  3  3* 

LAST   NOS 

Alteration    Dates 

7-^-03 

PIECE  NOS.  AFFECTED 

SJff        >.fcv 

a«t»    j«7 

1"  LOT  &  SHOP  NOS. 

livl/ 

?17' 

Proposed  by  :    Made  by  : 

jnf. 

HI.K. 

_ 

DATE     O.  tf.OZ, 

DRAWER  NO.  78 


DWG.  NO.   164-37 

l«~Sheets.    N.  15 


41 


FIG.  33.     REPRODUCTION   OF  A  MODERN   DRAWING  TITLE. 

list  of  the  pieces  affected  and  the  order  number  in  connection  with 
which  the  changed  drawing  was  first  used.  A  very  simple  way  of  do- 
ing this  is  illustrated  in  Fig.  34.  The  original  drawing — that  is  the 
drawing  as  first  ttsed  in  the  shop — is  called  Sub  No.  i.  Then  when  a 
change  is  made  that  in  any  way  affects  work  to  be  done  in  the  shop 
or  the  interchangeability  of  any  piece,  the  drawing  is  given  Sub  No.  2, 


EXPLANATORY. 

In   this  illustration  the   rectangle  A  BCD  represents   the~ drawing  trimmed  to  size,  and 
EFCD  is  the  Record  Strip    completely  filled  in  as  an   example. 

The  depth    ED  of  the  strip,"  which  for  very  small  drawings   may  be  about  /",    may 
conveniently    lye   tne  same  for   all  drawings  of  the  same  size. 

The  strip  should  be  divided  into  rectangular  spaces  suited'  to   the   contents,    which 
in    this   example   may   be  specified  as  follows :- 


Owq.  No. 

FIRM 

NAME     AND     ADDRESS 

Scale                                      Dwq.  No. 

Dmftemro's  5H^«»... 

CKTNMI 

»UB 

NO. 

First   Order  No. 
OK    Signature,   dared 

SUB 
NO. 

Fir«t  Order  Ne. 
O.K.  Siqnatur*.  dat«d 

TITLE 

Tracers  Signature 

hM 

Sf«) 

U'o 

Sub 
tk« 

emcnt    of    «h«t   tto 
wmq    was    untfcr  H*it 
N»,    tVia*    it   BEFORE 
charge     wa»     mad  1 

C^cWf  «     Siq-vrtur. 

Dcrtwi 

The  drawing  number,   which  should  be  in   bold  and  clear  figures,   appears  not  only 
at  each  'end   of  the  strip,   but  also  at  the    extreme  upper  left  hand  corner  A  of  the 
sheet,    where  if  is  inverted,  so  that   when  a   drawing   happens  to  be  piled  up    with 
others    wrong    way    around  its   number  may  always  be    read  right  way    up   in  the 
same    relative  position   on   the    sheet  —  the  lower  right  hand  corner. 

Those  parts  of  the   strip   that  are   common  to  all  the  drawings  of  the  same  firm   may 
with  aavantage   be  press  printed  on    the    tracing.      This  helps   to    uniformity. 


4378 

THf  AMFRICAN  MACHINE  CO^    Pittsburgh.  Pa..  U.S.  A. 

Scale   -zp                        4-3  "78 

O^ft^n.flV^Z 

1 

I*r0rdtr  No-  7/*2 

At'TbAi*.  3-S-ee 

ch  Rinq  wot  C.I. 
'9   was  3  "  long. 
r  326   wat  -fr'dia 

0  1  I^OrttK  No  8639 

£siex.*f*,&.* 

4-8  TRIPLE.  -GEARED  LATHE. 

MOTOR   DRIVEN 

VARIABLE  SPEED    MECHANISM. 
O£TA/tS. 

Tr*€tr.  e4f^.~rfM  •-« 

3-  4-.  OS 

Clut 

-!/« 
P>*c 

Chtdrtf-  Mf»U&*f 

B 


FIG.  34.     THE  RECORD  STRIP. 
42 


re-dated  and  signed,  and  under  Sub  No.  i  a  record  is  made  of  what  the 
drawing  was  as  Sub  No.  i ;  that  is  before  the  change  was  made  necessi- 
tating the  use  of  Sub  No.  2.  When  this  system  is  used  it  must  be  un- 


derstood by  all  concerned  that  references  to  drawing  numbers  always 
mean  the  latest  Sub  No.,  unless  otherwise  specified.  Other  suggestions 
regarding  the  use  of  the  record  strip  will  be  found  in  Fig.  34. 


CHAPTER    IX.     NOMENCLATURE    AND  WRITTEN    MATTER. 


130.  In  addition  to  the  contents  of  the  record  strip,  almost  all  me- 
chanical drawings  carry  more  or  less  written  matter,  as  names  of  pieces, 
designations,  bills  of  material,  explanatory  notes,  references,  and  spe- 
cial instructions;  all  of  which  depend  largely  for  their  efficiency  upon 
the  draftsman's  common  sense  and  knowledge  of  nomenclature. 

131.  Early  in  1905  it  was  the  writer's  privilege  to  prepare  a  pamphlet 
on   nomenclature  for  the  Westinghouse  Electric    &   Mfg.   Co.     The 
opening  paragraphs  of  this  pamphlet  read  as  follows: 

It  is  extremely  desirable  that  there  shall  be,  throughout  the  business  of  the 
company,  uniformity  in  the  naming  and  describing  of  apparatus;  in  other  words, 
uniformity  of  nomenclature. 

The  word  nomenclature,  as  here  used,  means  "full  descriptive  name,"  and 
covers  three  features: 

(1)  The  individual  terms,  or  "items"  of  a  name. 

(2)  The  sequence  of  the  items. 
-(3)  The  phrasing  of  the  items. 

The  system  of  nomenclature  outlined  here  is  intended  to  affect  names,  titles, 
indexing  and  filing,  throughout  the  Engineering  Department,  and  especially  in 
connection  with  the  following: 

Naming  of  complete  apparatus  and  of  parts  and  details. 

Wording  and  arrangement  in  printed  forms  and  on  nameplates. 


43 


Writing  of  specifications. 

Subjecting  of  correspondence. 

Titling  of  drawings. 

Titling  and  wording  of  catalogues  and  circulars. 

Indexing  and  filing  in  general. 

132.  The  pamphlet  is  thumb-indexed,  so  that  the  name  of  any  machine 
or  apparatus  can  be  referred  to  instantly.  The  official  method  of  de- 
scription is  read  from  numbered  columns  of  classified  data,  as  shown 
in  Fig.  35,  which  is  a  reproduction  of  the  page  devoted  to  circuit  break- 
ers. The  sequence  of  items  is  obtained  by  reading  "down"  as  num- 
bered under  "items."  Items  connected  by  dashes  are  the  equivalent 
of  a  single  item,  and  may  be  termed  a  "set";  except  when  part  of  a  set 
no  two  items  from  the  same  line  can  be  used  at  once.  The  preferred 
"phrasing"  is  indicated  in  the  table  by  numbers  under  that  head;  the 
system  of  nomenclature  requires  the  use  of  one  written  line  per  phrase, 
as  in  the  following  example  description  of  a  circuit  breaker: 

Circuit  breaker:  carbon:  type  A. 
Hand  operated:  overload  release. 
Five  amperes:   120  volts,  D.  C. 
Four  poles:   i6-in.  throw. 


In  this  example  the  items,  their  sequence  and  phrasing  are  in  accord- 
ance with  the  table. 

133.  In  the  titling  of  a  drawing  it  is  not  always  desirable  to  use  a  full 
description  of  the  apparatus;  none  but  orthodox  names  should  be  used, 


rki*M> 

Itema 

Name 

1 

1 

CIRCUIT  BKEAKKR 

2 

Carbon    :   Oil   :   Fuaed   :    Mac.  BlowOM    :   Air 

1 

Type  (•«.  A,  B.  C.  D) 

» 

4 

Hand  Operated     Blec.  Operated          Pneumatic 

; 

Front  Connection    :    Rear  Connection 

( 

Swbd.  Monntlnf  :  Wall  Mounting  :  Direct  Control 

7 

CKrtrload:                   O.  L.  and  O.  V.   1 
Underload:               U.  t.    "    U.  V.   iReleaM 
Orer  Voltage:           Non-Automatic  J 
Under  Voltage: 

1 

• 

Ampa.  VolU  A.C.  Volta  D  C. 

•     4 

1 

Fote.  Thro, 

FIG.   35. 


Ctrenlt 

SAMPLE    PAGE    OF    WESTINGHOUSE    PAMPHLET    ON 
NOMENCLATURE. 


however;  and  when  possible  the  official  sequence  and  phrasing  of  the 
items  should  be  employed,  as  in  the  following  example  title: 


Circuit  Breaker:  carbon:  type  A 

Hand  operated:  overload  release 

General  Drawing 


134.  Just  how  it  came  about  that  the  matter  of  nomenclature  received 
this  special  attention  from  the  Westinghouse  Company  has  so  direct  a 


bearing  on  the  leading  features  of  this  chapter  that  a  brief  account  may 
not  be  out  of  place  here. 

135.  In  1899  the  drafting  room  of  the  above  company  was  finding 
employment  for  something  over  one  hundred  men,  and  up  to  that  time 
about  25,000  drawings  had  been  made  and  put  on  file.     The  chief 
draftsman,  a  Mr.  John  W.  Meserve — then  newly  appointed — a  man  of 
great  executive  ability  and  of  long  experience  in  the  managing  of  large 
drafting  rooms,  was  dissatisfied  with  the  lack  of  system  that  he  found, 
but  it  was  impossible  for  him  to  devote  time  to  a  thorough  investigation. 
The  making  of  this  investigation  fell  to  the  writer's  lot.     A  study  of 
conditions  revealed  among  other  things  much  confusion  in  the  matter 
of  nomenclature.     Different  men  called  the  same  thing  by  different 
names,  or  what  was  quite  as  bad,  meant  different  things  by  the  same 
name;  and  drawings  that  were  titled  similarly  did  not  contain  similar 
parts;  so  that  the  drafting  room,  office,  and  shop  were  continually  mis- 
understanding one  another. 

136.  An  important  step  was  made  leading  toward  a  system  of  no- 
menclature when  the  first  "element  chart"  was  developed,  as  repro- 
duced here  in  Fig.  36.     This  is  one  of  about  thirty  that  were  compiled. 
Each  machine  was  divided  into  "elements,"  each  element  consisting  of 
certain  specified  details,  and  every  part  was  officially  named.     With 
these  charts  in  their  possession  draftsmen  had  no  excuse  for  using  ir- 
regular names  or  titles,  and  their  influence  was  soon  felt  throughout 
the  factor)',  so  that  in  talking  or  writing  about  details  of  construction 
there  came  to  be  less  and  less  misunderstanding,  and  a  much  more 
harmonious  condition  prevailed. 

137.  These  element  charts  almost  immediately  led  to  the  adoption, 
for  each  type  of  machine,  of  special  printed  lists — called  "drawing 
lists" — for  the  transmission  of  information  from  the  drafting  room  to 


44 


STATIONARY  PART 


ELEMENTS 


DETAILS 


FBAME 


JACK 

v 

Jacti  beam 

BCD  PLATS  I***™**"*1** 


Frame  castings. 

oies  |  garf^  ff,,efS 

Headless  set  screw  for  locating  worm  shaft  bushing. 
Stud  -  bolt  &  nuts.   Eye -bolts.  Liners. 

Jack  beam  &  screw. 


,  ClS'&t   A  S: 

Q.    -     -^    .--> 


•a  Bed  plate  casting.  Guide  &  screws. 
3  Bed  plate  bolts  A  nuts.fbot*  for  frame  t 


ROCKER  RING 


ROCKS  if  RING  GEAR 


Ring  costings.  Stud-bolts  t  nuts,  (when  ring  « in  half} 
Guide  pieces  £  tap-bolts. 


Wor.m  wheel  segment.    Tap  bolts. 
Worm.   Worm  shaft. 
Bushing.    Collars.   Pins 
%  Hand  wheel. 


..  ..      Copper  rings.    Cleats,   Bolts,  efc. 

BRUSH  CROSS  CONNECTIONS    LJ|    \*cantact  plates. 

W-Uaf*         I     &.T*>r-minfiJ   n/af-fu 


BRUSH  HOLDER  BRACKET 


t          Bracket  casting.    Set  screw  8,  rtt/t. 
t*-_   Bofte  for  bracket,  contact  plate  &  brush  holders. 
•^-Insulations,  washers  &  washer -plates. 

Casting 


Holder.  Support.  Pressure  p/afe  &  thumb  screw. 
Tension  spring.  Scrfnf  Fnut.  Shunts.    Screw  &  washer. 
Shaft.  Bush  &  taper  pin. 


ROTATING  PART 


ELEMENTS. 


DETAILS 


ARMATURE 


ven t  piaf»         %  Spider  casting. 

f/nyer  plafe  \       [net  pinto  fyPunchtnQS . 

Amhrion  ( [ #Mentilatin$  plates 

•%Finger  plates. 
XEnd  plates, 

rfeys. 

•% Commutator  bars. 
•^Commutator  ring;  studs,  nuts  &  washers 

Insulation. 


•j»Mtar 


ARMATURE  COIL 
ARMATURE  COIL  SUPPORT 


ARMATURE  CROSS  CONNECTIONS 


SHAFT  (Nat  usually  furnatxji 


See  Flee.  8,  Insulation  Specification. 


Casting  t  xrfia. 
Insulation  t  rivets. 


Cleats.  Studs 
Connectors.  Cabin. 


Shaft. 


'  Parts  marked  thus  are  detailed 


APOUNO  FRAME 


LAMP  CIRCUIT 


Base 
^Contact  t>/ocfo.  Bolts  &  washers. 


Field  coils.  Coil  hangers,  bolts  &  washers. 
Leads.  Strips.  Bolts.  Washer  plates  £  nuts. 


Shunt,  series  S  cable  connectfons.    Cleats  A  screws. 

Bolts,  ferrufes  A  rubber  washers  for  attaching  term  bd 
-^Terminals. 
•%Name  plates. 


Chandelier.   Lamps. 
Cleats.  Lamp  wire. 


FIG.  36.     AN   "ELEMENT  CHART.' 


the  shop.  This  was  another  step  in  the  right  direction.  In  these  lists 
the  correct  names  of  the  parts  were  arranged  in  the  same  order  as 
on  the  charts.  Finally  in  order  to  insure  uniformity  in  the  describing 
of  complete  apparatus,  the  pamphlet  on  nomenclature  was  written. 

138.  Very  little  need  be  said  here  about  Iw-w  to  give  a  name  to  a  piece 
of  machinery,  except,  perhaps,  that  it  should  never  be  done  thought- 
lessly.    While  a  new  machine  is  being  designed,  it  should  be  divided 
into  natural  or  suitable  "elements,"  and  these  into  "details"  sensibly 
named.     It  is  not  at  all  uncommon  to  find  included  in  the  name  of  a 
piece  the  name  of  a  material.     This  is  distinctly  poor  practice.     The 
already  established  principle  that  "drawings  should  be  made  right  to 
stay  right"  has  a  direct  application  here;  if,  for  instance,  terms  like 
"wooden  ring,"  "fiber  washer"  are  allowed  to  creep  in,  and  it  is  de- 
cided later — we  will  say  a  year  later  after  all  catalogues  and  circulars 
have  been  issued  using  these  terms — that  the  ring  is  better  of  fiber  and 
the  washer  of  brass,  there  have  been  introduced  two  very  absurd  names, 
for  we  shall  have  a  wooden  ring  made  of  fiber  and  a  fiber  washer  made 
of  brass;  and  it  will  not  be  at  all  an  easy  matter  to  stop  the  use  of  these 
names. 

139.  In  most  drafting  rooms  the  naming  of  parts  and  details — where 
names  are  used  in  preference  or  in  addition  to  numbers — is  done  with- 
out sufficient  consideration;  a  habit  of  carelessness  too  often  prevails, 
the  result  being  names  that  do  not  fit  and  that  cause  trouble  in  many 
little  annoying  ways.     The  remedy  lies  almost  entirely  in  a  personal 
appreciation  of  the  necessity  of  using  care. 

140.  But  the  name  of  a  piece  is  only  a  part  of  what  may  be  called  the 
draftsman's  designation  of  it,  which  often  includes  several  items,  as  di- 
mensions, material,  finish,  and  quantity  required.    Taking  the  last  of 
these:  On  the  first  thought  it  would  not  seem  difficult  to  find  one  way 


— one  universally  acceptable  way — of  specifying  quantity  required;  and 
yet  an  examination  of  the  drawings  made  by  different  men  in  different 
drafting  rooms  revealed  a  variety  quite  surprising  in  its  range.  The 
following  are  some  of  the  different  ways  in  which  English-speaking 
draftsmen  have  specified  required  quantities  in  actual  working  draw- 
ings made  during  the  past  fourteen  years: 


3 

Three 
3  wanted 
3  needed 
3  of  these 
3  of  them 
3  of  this 
3  off 
3  of 


Take  3 

Use  3 

(let  3 

3  thus 

make  3 

•Want  3 

3  ref|vind 

3  like  this 

3  per  machine. 


141.  And  this  variety  in  the  term  is  supplemented  by  changes  of  its 
position  in  the  complete  designation;  thus,  taking  a  simple  example,  a 
complete  designation  may  read: 

Make  3  Dowel  pins  }-in.X3i-in. 
or  j-in.X3}-in.  Dowel  pin,  make  3 
or  Make  3— J-in.X3}-in.  Dowel  pins. 

142.  But  to  return  to  the  manner  of  specifying  quantity  required; 
during  the  investigation  already  referred  to  it  was  finally  decided  to  use 
"Require" — abbreviated   "Req." — and   to   follow   it  by  the  quantity 
number,  as  Req.  3:  the  great  advantage  of  this  word  is  that  it  is  gen- 
eral in  its  significance,  for  whether  a  piece  has  to  be  made,  or  bought, 
or  taken  from  stock,  it  is  always  "required."     It  was  further  decided 
that  in  all  designations  this  should  be  the  last  item,  thus: 

J-in.X3j-in.  Dowel  Pin:  Req.  3. 


46 


The   designations   given    below    are    representative    examples  for  draftsmen   to   imitate.    Many  of  them   follow 
commercial  usage.    As  a  general  rule,   in   specifying  pieces  of  raw  material,  as    wire,   rod,    sheet   and  strap,  the 
thickness    or  diameter  is   given    after    the   other   dimensions-,    in    specifying  finished  articles,  as  screws,   bolts, 
rivets  and  escutcheon  pins,    the   diameter   should  be   given  first. 

In    these   examples,   to    avoid   tiresome   repetition,    the  "guantity   required    is    generally   omitted. 


FASTENERS 

j  x  3&  Dowel  pin,  Reg.  3 

T'X  6-z  M.B.  Mach.B.,  Reg.  15 

¥  x9~Stud,   Reg.  38 

-f"*2i"M.B.  Tap.  B.,  N.P  Reg.  8 

f~  x  li"  Cap  Sc.,  C.H.Hd. 

73   x  I*.  Spring  Cotter 

*I6  x%~  Escutcheon  pin 

T  *  ?  x  4  'Feather  .  key,  steel,   Req.  2 

i  x  2i"Lag  Sc. 

I*  Hex.  Nut 

T  Lock  nut' 

Wing   nut,  *73,  Reg.  8 

i'x  l£  '  Rd.  Hd.  I.  Rivet 


x  -s  Flat  Hd.  I.  Rivet 
J6  x&  F/at  Hd.  Csk.  Copper  Rivet 
#9  x-j-  Copper  be  It-  rivet 
32  x^  Copper  jacket-  rivet 
-fxl&'Pin,  C.R.S..  Reg.3l 
#14-24-  *li*Fi/.  Hd.  B.  M.Sc. 
Hex.  Hd  Set  Sc.  *248.  Reg.  BO 
~j   Eye  bolt,  Req.  I 
Jack  Sc.  *74J,  Reg.  I 
i"x  /"  Hdlss.  Set  Sc.  C.H.,  Reg.2 


INSULATING    MATERIALS 
3sk-  x  5&  x  TS  Sh.  Asbestos,  Reg.  3 
Distance  piece,  24-*x  I2"x-g  fibre 
1?  x  TG  Rod,    red  fibre.,   Reg.  6 

3  Layers  of  "056  F.B.,  for  building 
up   coils   to  /£*\  Reg.  16 

3  Layers  of  *056  F.B.,  Treated  and 
cemented  together  with  shellac. 

//"*3/i  x  js  Mica,  Reg.? 

S  x  %  Rod,  semi  -hard  rubber. 

22  "  x36~x  2  v  Soaps  f  one 

ROD 

lz*'x  *.  085  Drill  rod,  Reg.3 

*6  -32  Nut,  from  £x  f  Hex.  B.  Rod. 

From  half  round  ".162  B.  Rod,  i  long. 

SHEET  &  PLATE 

Punchings  of   *0/72  sheet  steel 
"\  0625  Steel,  3  at  each  end,  Reg.  6 
x  82'  '*%'  'Plate,  steel,  Reg.4- 


TUBING 

3+*  of  "8718  x  I"  Seamless  B.  Tubing 
%'*£'  w.l.  Pipe,   Req.  21^ 


MISCELLANEOUS 
4  Lock   washer,   Req.  3 
8-^ of  ".007  G.S.  Wire,  Reg.  6 
10  Turns  of  "024- Music  wire,  Reg.  8 
*/2  Torpedo  twine,  Reg.  20  Ft. 
r*5~ Felt;  cut  to  suit,  Reg.3 
l"x  4--S* x  •£' Pad,  L eather. 
7*~/6  Thds. 
#24—16  Tap. 

-f  Tap,  II  Thds.  per  inch. 
:20I  Drill  &  /FOv.,  jr'cteep. 
Made  from  /jx/6   Copper  strap, 
about  2^-  long,  Reg.3. 

Taper  1*219  per  foot  on  diameter. 
3~x  IO*x-$:~ Hard  wood,    Reg.2 


The  above   examples    indicate    when  a   word  should  begin    with  a  capital  letter.     In  general,    capitalize    the  first 
word  in   a   designation^    all  abbreviations,  and  the    word  immediately  following  an   abbreviation. 

An    explanatory   or  descriptive  note   added  as  auxiliary   to    the*}        « 

designation^  shou/d  be  placed   under   the  designation,  so   as   to     [     •%  x  6   Tap  B.,  Head  S.F 8.  Blued,   Reg.8 
leave    the  "quantity  reguired"  at  the  end  of  a   line,   thus :-  )  For  securing  bracket  to  leg. 


FIG.  37.     EXAMPLES  OF  DESIGNATIONS. 


PHYSICAL    QUANTITIES:  Symbols. 

Length L,  I 

Mass M 

Time T\  * 

Surface s-  3 

Volume V 

Velocity,  linear v 

angular cj 

Acceleration " 

Force,  <*•  weight f.f 

Worn W 

Power. P 

Pressure P 

Moment  of  inertia K 

METALS 

A/uminurri A/ma. 

Babbitt 86. 

Brass B. 

Bronze Bz. 

Carbon Cbn. 

Cast  brass.. C.B 

Cast  copper. C.Cop. 

Cast  iron C.I. 

Cast  steel C.S. 

Cold  rolled  ttetl C.R.S 

Copper Cop 

Lead Lead 

Malleable  iron M.I. 

Open   hearth  steel O.H.S. 

Phosphor  bronze Ph  Bz. 

Steel Steel 

Stetl  casting S.C. 

Wrought  iron W.I. 

Zinc  .  .  ..  2n. 


GAUGES 

Brown  S  Shorpe,  ..............  ___  .........   3  &S 

or  American  Standard  Wire  Gauge 
Birmingham,  ...................  .  ........  B.W.G. 

or  Stubs'  Iron    Wire  Gauge 
National  ...............................  N  W.  0 

or  Rorblinq's,  or  Washbum  i  Motn's 
Music    Wire  Gauge  ...........  .  ........  M.  WG 

United  States   Gauge  __________________  US  G 

Twist  Drill  &  Stetl   Wire  Gauge  ............  T.O.G 

Stubs'  Steel  Wire  Gauge  ..................  S.WG 


Dfc  3-  °6 


THE   MONTHS 

Jan      Feb.     Mar.     Apr.     May     June. 
July     Aug    Sept      Oct.       Nov.       Dec. 

TIME 

By   the  clock  .....................  Zh  I5m  +6* 

Duration  ...  .  .  Zh  15m  4-6s. 


FASTENERS 

Button  head  bolt. Btn   Hd  ff.' 

Cap  screw ,Cap  Sc. 

Double   chamfered  hexagon  nut: 

DM   Chmfd  Hex.  Nut 

Eye  bolt. Eye  B. 

Fillister  head  brass   machine  screw : 

Fil.  Hd  B.  M.  Sc. 
Fillister  head  iron    machine  screw: 

Fil.  Hd.  I.  M.  Sc. 

Flat  head    wood  screw Flat  Hd.  Wd.  Sc. 

Flat  head  stove  bolt. Flat  Hd  Stove  B. 

Headless   set  screw _ Hdlss  Set  Sc. 

Hexagon    nut. Hex.  Nut 

Lag  screw Lag  Sc. 

Machine    bolt .Mach.  B. 

Machine  screw    nut. .M.Sc.  Nut 

Milled  body   tap   bolt. M.B.  Tap  B. 

Set  screw .  . Set  Sc. 

Square    nut So.  Nut 

Stud  bolt Stud  B. 

T-head  bolt T-Hat.  B. 

WEIGHTS  &  MEASURES,   etc. 

Center. Cr. 

Center   line --€r. 

Centimetre em. 

Circular  mils C.M. 

Circumference Circum. 

Diameter. alia. 

Electromotive  force E.M.F 

Foot,  feet. Ft. 

Horsepower HP 

Inch,  inches In. 

Kilogram _ Kg. 

Kilometre  Km. 

Kilowatt .„...  KW 

Millimetre mm. 

Ounce,    ounces - 0z. 

Pound,  pounds.. Ib. 

Radius ..  ...  Rod  or  R. 


X'  Here  the   meaning    of   the  abbreviation 
depends    entirely    upon    how    it  is    used.    This  is 
largely    true    of  most  abbreviations,  f 

In    "a  lamp    of  16  C.P."it  is  perfectly  evident 
that    the    meaning    is    'candle  power." 

In    "a  gear    of  -j:"CP,  72  reeth"  it  is   just  as 
evident  that    the  abbreviation    means    'circular 
pitch'. 


MISCELLANEOUS 

Alternating  current A.C. 

Amperes Amp. 

Board Bd 

Bracket. Bkt. 

Building Bldq 

^.(Candle  power C.P 

'*\Circular  pitch C.P. 

Case  harden C.H. 

Compan  y ._ Co. 

Counterbore Cbr 

Countersink Csk 

Cylinder Cyl. 

Degrees  Centigrade IO*C 

Degrees  Fahrenheit lO'F 

Department. Dept. 

Direct  current- D.C 

Drawing. Dwq. 

Electrical. Elec. 

Experiment.. E*f>. 

Feather. Fthr. 

Flexible Flex. 

General Gnl. 

Hexagon Hex. 

Machine Mach 

Manufacturing Mfg 

Material.. Mtl. 

Maximum Max. 

Minimum Min. 

Negative Neo 

Not  to  scale N.T.S. 

Nickel  plate N.P. 

Number  :  For  designating No.  or  & 

Number  :  Quantity. Nbr. 

Pattern  number. Pat.#3l78 

Per  cent. °/o 

Positive Pos. 

Railway Rwy. 

Revolutions  per    minute RPM 

Rotating  part. Rotor 

Round Rd, 

Seamless Smlss. 

Sketch 5*. 

Specification Spec. 

Square .- Sq. 

Standard S-td. 

Stationary  part. _ Stator 

Temperature Tern  p. 

Threads Thais. 

Weight Wgt. 


Unless    the    words  adjacent    to  an    abbreviation    unmistakably    suggest   its    true    mtaning,    the 
obtrtviation    should  not  be    used 


48 


FIG.  38.     EXAMPLES  OF  ABBREVIATIONS. 


In  this  arrangement  there  is  no  danger  of  confusing  the  "quantity  fig- 
ure" with  any  other  figure  in  the  designation. 

143.  The  example  designations  presented  in  Fig.  37  are  intended  for 
draftsmen  to  imitate.     It  will  be  noticed  that  in  many  of  them  abbre- 
viations are  quite  freely  used.     In  this  connection  it  is  not  easy  to  lay 
down  any  very  useful  principle,  except  perhaps  to  say  that  it  is  per- 
missible to  abbreviate  any  term  i}  it  is  quite  certain  that  no  misunder- 
standing -will  ensue. 

144.  It  has  so  long  been  the  habit  of  draftsmen  to  designate  the 
much  used  metals  by  their  initial  letters,  that  the  custom  may  be  looked 
upon  as  practically  universal.     With  regard  to  abbreviations  in  general, 
the  writer  is  somewhat  chary  of  making  suggestions.     In  designations 
and  tabulated  information — such  as  bills  of  material — they  are  almost  a 
necessity,  in  order  to  get  compactness;  it  would  certainly  be  a  hardship 
if  draftsmen  were  compelled  to  use  the  full  term  "fillister  head  iron 
machine  screw."     On  the  other  hand  a  promiscuous  use  of  abbreviations 
in  written  notes  should  be  avoided,  as  should  any  term  of  doubtful 
meaning.     Some  abbreviations  that  have  been  found  useful  are  listed 
in  Fig.  38. 

145.  It  is  often  convenient  to  use  commercial  or  "trade"  terms  on 
drawings.     Unfortunately  many  of  these  terms  and  their  meanings  are 
subject  to  change  without  notice;  and  again  the  same  term  may  have 
different  meanings  in  different  parts  of  the  country;  but  we  have  as 
yet  no  recognized  standard  dictionary  of  mechanical  terms,  so  that  the 
whole  condition  of  affairs  is  beyond  the  draftsman's  control  and  is 
something,  therefore,  that  it  is  useless  for  him  to  worry  about.     The 
draftsman  should,  however,  know  the  difference  between  a  washer  and 
a  sleeve,  between  a  bolt  and  a  screw,  a  shoulder  and  a  collar,  a  lever 
and  a  link,  and  he  should  know  the  meanings  of  all  the  simpler  me- 


chanical terms,  many  of  which  the  average  draftsman  of  to-day  uses 
with  very  little  discretion.  The  following  are  a  few  definitions  that 
the  writer  developed  for  his  own  benefit  when  at  the  board;  they  are 
given  here  merely  as  examples: 

A  washer  is  a  circular  plate  of  uniform  thickness  with  a  circular  hole  through 
the  middle. 

A  washer-plate  is  a  plate  used  as  a  washer  that  is  not  fully  described  by  the 
term  washer;  thus  it  may  be  square  and  have  several  holes  in  it. 

A  lock-washer  is  a  washer  specially  designed  to  prevent  a  threaded  nut  from 
jarring  loose. 

A  collar  is  a  ring  of  any  shape  secured  around  a  shaft  or  similar  part  when 
placed  there  as  an  end  bearing  or  stop.  A  shoulder  should  never  be  called  a  collar. 

A  bush  is  a  tube  of  any  shape  that  either  is  or  is  not  secured  to  what  sur- 
rounds it  but  that  is  not  secured  to  what  it  surrounds. 

A  sleeve  is  a  tube  of  any  shape  that  either  is  or  is  not  secured  to  what  it  sur- 
rounds but  that  is  not  secured  to  what  surrounds  it. 

146.  At  a  banquet  given  some  years  ago  to  a  special  graduating  class 
in  mechanical  drawing,  one  of  the  guests — an  engineer  of  national  re- 
pute— spoke  to  the  following  effect : 

"Don't  be  afraid  of  using  the  English  language  on  your  drawings;  don't  be 
stingy  in  the  use  of  notes.  Remember  that  the  man  in  the  shop  is  not  a  mind 
reader,  and  a  brief  note,  carefully  worded,  will  often  save  the  shop  much  uneasi- 
ness. The  majority  of  draftsmen  seem  to  think  it  a  sign  of  weakness  to  resort  to 
writing,  and  go  out  of  their  way  to  avoid  notes.  I  assure  you  it  is  not  only  legiti- 
mate, but  absolutely  necessary  to  make  use  of  notes  if  you  are  to  become  master 
draftsmen.  But  whatever  you  do,  word  them  carefully,  and  don't  forget  to  in- 
dent your  paragraphs;  and  remember  that  an  ambiguous  note  is  worse  than  none 
at  all.  Don't  speak  of  the  right-hand  side  of  a  piece,  or  the  front  or  the  back; 
mark  the  particular  side  with  a  reference  letter;  you  see  the  man  in  the  shop  when 
looking  at  the  piece  may  be  standing  on  the  other  side  of  it;  then  what  was  right 
to  you  is  left  to  him,  and  that  may  cause  trouble." 


49 


CHAPTER   X.     CHECKING. 


147.  Before  drawings  are  permitted  to  go  to  the  shop  they  should  be 
systematically  checked.     In  large  drafting  rooms  it  is  now  quite  gen- 
erally the  practice  to  have  certain  men  do  nothing  else  but  check  the 
work  of  the  draftsmen.     This  checking  is  of  vital  importance;  mistakes 
are  not  mistakes  until  after  they  have  eluded  the  checker's  eye.    A 
drawing,  like  a  machine  or  other  manufactured  product,  is  not  ready 
for  use  until  it  has  been  officially  inspected,  and  perhaps  tested. 

148.  The  following  suggestions  are  intended  as  a  help  to  systematic 
checking.     Each  feature  should  be  taken  up  separately  and,  if  possi- 
ble, each  phase  of  the  work  completed  before  passing  on  to  the  next. 

1.  Put  yourself  in  the  position  of  those  who  are  to  read  the  drawing 
and  find  out  if  it  is  easy  to  read  and  tells  a  straight  story.     Always  do 
this  before  checking  any  individual  features;  in  other  words,  before 
you  have  had  time  to  become  accustomed  to  the  contents. 

2.  See  that  each  piece  is  correctly  illustrated  and  that  all  necessary 
views  are  shown,  but  none  that  are  not  necessary. 

3.  Check  all  the  dimensions  by  scaling,  and,  where  advisable,  by 
calculation  also. 

4.  See  that  dimensions  for  the  shop  are  given  as  required  by  the 


shop,  that  is,  that  the  shop  is  not  left  to  do  any  adding  or  subtracting 
in  order  to  get  a  needed  dimension. 

5.  Go  over  each  piece  and  see  that  finishes  are  properly  specified. 

6.  See  that  every  specification  of  material  is  correct  and  that  all  nec- 
essary ones  are  given. 

7.  Look  out  for  "interferences."     This  means  check  each  detail  with 
the  parts  that  will  be  adjacent  to  it  in  the  assembled  machine  and  see 
that  proper  clearances  have  been  allowed. 

8.  When  checking  for  clearances  in  connection  with  a  mechanical 
movement,  lay  out  the  movement  to  scale,  figure  the  principal  angles  of 
motion  and  see  that  proper  clearances  are  maintained  in  all  positions. 

9.  See  that  all  the  small  details,  as  screws,  bolts,  pins,  keys,  rivets, 
etc.,  are  standard  and  that  where  possible  stock  sizes  have  been  used. 

10.  Check  every  feature  of  the  record  strip. 

11.  Review  the  drawing  in  its  entirety  in  connection  with  any  points 
that  have  suggested  themselves  during  the  above  checking. 

12.  Bearing  in  mind  the  value  of  explanatory  notes,  do  not  fail  to 
add  such  notes  as  your  experience  tells  you  will  increase  the  efficiency 
of  the  drawing. 


50 


CHAPTER   XI.     STANDARD    DATA. 


149.  In  every  manufacturing  concern  in  the  world  there  are  certain 
facts  and  certain  methods — in  other  words  certain  "data" — that  are 
used  over  and  over  again.     When  these  data  are  collected,  classified, 
and  tabulated  for  general  use  they  are  called  standard  data. 

150.  In  many  drafting  rooms  the  importance  of  collecting  standard 
data  is  recognized,  but  the  manner  of  tabulating  is  probably  not  the 
same  in  any  two  drafting  rooms  in  existence.     This  is  unfortunate, 
because  it  makes  it  inconvenient  to  bind  together  the  data  collected  by 
different  men  and  different  firms — data  of  general  value  that  might 
otherwise  be  made  use  of  in  the  compilation  of  a  standard  book  for 
universal  use. 

151.  The  main  objects  in  view  here  are  to  suggest  for  the  adoption 
of  drafting  rooms  in  general  a  standard  size  for  standard  data  sheets, 
and  to  present  some  methods  of  tabulating  that  have  been  developed 
with  the  idea  of  making  the  data  easy  to  read. 

152.  The  dimensions  and  general   arrangement  suggested  for  the 
sheet  are  given  in  Fig.  39,  with  an   inset  illustration  of  the  "master 
tracing"  which  carries  a  special  record  strip  for  the  recording  of  sub- 
number  changes.     The  sub-numbers  and  their  dates  are  repeated  in 
the  lower  margin  of  the  trimmed  sheet;  the  same  margin  also  carries 
the  firm  name  and  address,  signatures  and  drawing  number;  leaving 


a  clear  rectangle  for  the  data.  The  trimmed  sheet  is  the  same  size  as 
the  widely  known  Carpenter  section  paper,  \z\  in.  X  8£  in.,  small  enough 
to  handle  comfortably  when  bound  in  book  form,  yet  large  enough  for 
the  clear  tabulating  of  data.  When  it  is  desired  to  file  with  correspon- 
dence, it  is  only  necessary  to  cut  off  the  i^-in.  binding  strip  and  the 
sheet  is  "letter  size" — 8£  in.  X  n  in. 

153.  When  putting  together  a  page  of  data  for  general  reference  it 
is  impossible  to  be  too  careful  about  the  arrangement  and  ruling  of  the 
sheet.     Data  should  always  be  easy  to  read,  and  every  sheet  should 
contain  such  explanatory  notes  as  are  necessary  to  make  the  meaning 
of  it  all  perfectly  clear. 

154.  Figs.  40  to  43  are  four  pages  from  the  standard  book  of  the 
Westinghouse  Company,  introduced  here  to  illustrate  certain  methods 
of  tabulating  that  have  been  found  decidedly  helpful.     The  reader  will 
easily  realize  that  the  sheets  were  compiled  with  considerable  care,  but 
his  attention  is  directed  particularly  to  the  studied  irregularities  in  the 
arrangement  of  the  columns  and  in  the  general  ruling  of  each  sheet. 
Thus,  in  Fig.  40  the  columns  are  purposely  staggered — this  makes  them 
stand  out  far  more  clearly  than  if  they  were  all  on  the  same  level;  then 
every  fourth  horizontal  line  consists  of  short  heavy  dashes — these  are 
guide  lines  for  the  eye,  and  make  it  easy  to  follow  horizontally  from 


51 


.  Edge  of  sfieef   trimmed  ready  for  binding. 


5     . 


TITLE 


10' 


13' 

of  trucmq. 


• 

This   ftprestntt    what    may  , 
thf  "matter  tracing"  of  tht 

>*  ttrmtd 
t  tandard 

• 

All   bJutprints    for    diftribttt 

binding  should  be   fn/nmea1 
rtc+anqlt  ABCDt   I2i~  *  ft 

on   Of 

to  tht 

L  i   J 

J 

*—  Record  strip  fTo  **  /«/»««*  »n  *t  *****) 

THC.     MA3TCR     TOtCINO. 


\,Sut>  No. 


Signatures 


I     I  Date 


T 


I    I  I 


FIRM   NAME  &  ADDRESS 


'"k 


DWG.  NO. 


FIG.  39.     DIMENSIONS  AND  FORM  OF  STANDARD  DATA  SHEET. 


UNIT   CHORDS 


Nbr. 

OF 

SIDES 

~2~  ANGLE 

UNIT 
CHORD. 

Nbr. 

OF 
SIDES 

2"  ANGLE 

UNIT 
CHORD. 

Xj^v 

When   diameter  =  / 
Chord  =  Sine  -Bangle 

1  EXAMPLE:  When  ctia  =  /" 
land    the  Nbr.  of  sides  =  5  : 
Readinq    from   Table, 
ingle  =36°  Sine  36°-SS77SSS 
.5877SSS  x  7  =  4".  1144964- 

Nbr 

OF 
SIDES 

~2~  ANGLE 

UNIT 
CHORD. 

Side  *  Chord  - 

14- 

12°-5l'-25".7l 

.2225208 

52 

3'-  27-4,"  S3 

.O6O37S4 

27i 

6'- 

.1139923 

f4i 

l2°-24-49".6S 

.2/49756 

53 

3°-  23'-46".4/ 

.  05924O5 

28 

6'- 

25-42".SS 

.11  19644- 

15 

12° 

.20791/6 

54 

3°-2o' 

.  0581448 

28i 

6'- 

18'-  56".  84- 

•  IIOOO54 

15 

/ 

ll°-36'-46".4S 

.2O/3O27 

55 

3°-l6'-2i:S, 

.0570887 

Nbr. 

OF 
SIDES 

•£•  ANGLE 

UNIT 
CHORD. 

c" 

29 

6'-  12-  24".  f  2 

.1081189 

16 

7/~-7/' 

./950903 

56 

3°-J2'-Sl".42 

.O56O7O4 

29? 

6°-6'-6".to 

./  062  936 

16 

/ 

10°-  S4-32".7Z 

.1892537 

57 

3°-9-  2S".4Z 

.05  SO  877 

J 

60° 

.8660254- 

2 

30 

6° 

.  1045284 

17 

/O°-  35-  17.  '64- 

.1837495 

58 

3°  -6-  ia".4l 

.0541388 

3j- 

S/'-25-43" 

-7709081 

31 

,S°-'rg-33".22 

./Oil  683 

17 

•/ 

10°-  17'-  8".57 

./78S574 

59 

3°-3'-3".OS 

.OS  3222  1 

4 

45" 

.707IO68 

S 

32 

5°-37-3o" 

•098OI7I 

18 

10° 

•  I73648/ 

60 

3° 

.  O52336O 

x2  ' 

40° 

.6427871 

33 

S°-27'-/6".36 

.  095O560 

•^j 

I8i 

9°-43'-47.'02 

./69003O 

61 

2°-S7~-  2".  95 

.  0514787 

5 

36° 

•5877852 

34 

S°-  /?-  38".ff2 

.0922683 

19 

9°-  ZS'-  2S".26 

•  1  645945 

62 

2°-54-  t/'.6f 

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j-  1 

3Z°-43'-38" 

.540  64-01 

35 

5°-S-34".28 

.  O896392 

3s 

19-2- 

9°-  I3'-5O.77 

./6O4/4O 

63 

2°-  S/'-Ss".7l 

.0498458 

6 

30° 

•  5 

36 

5° 

.0871557 

20 

9° 

.  /  56  4344 

64- 

2°-4S-45" 

.0490676 

£  / 

Z7°-4l'-32".30 

.4647408 

37 

4°- 

5l'-53"5/ 

.  0848O53 

U  2 

20t 

8'-46'-49*. 

74 

.  /S  265/6 

65 

2°-46'-9".23 

.0483/33 

7 

25°-42'-5l".4Z 

•4338837 

38 

4°-44-  /2".63 

.0825793 

21 

S°34-/7"t4 

.  /490422 

66 

2°-43'-38"./8 

•  O  47  58/9 

7/ 

2.4° 

.4067366 

39 

4°-36'-SS'.3S 

.0804665 

/£ 

21* 

8°-  22-  /9".S3 

•  /4S5536 

67 

2'-4l'-l/".64 

•  0468722 

<? 

22°  3o' 

•3826834 

4-0 

4°-3o' 

.0784591 

22 

8°-  10-  54.54 

J423I48 

68 

2°-38'-49".4! 

.  O46I834 

<?J 

21*-  10'-  3S",3 

•  38/2528 

41 

4°-23-24".f7 

.  0765492 

22i 

8° 

./39/73I 

69 

2°-36'-3/*30 

.  O455/45 

5 

20° 

•342  O2  O/ 

42 

4"-  I7~  -g".  57 

.07473OI 

23 

7°-  49-33".  91 

.1361666 

70 

2°-  34-  17''  14 

.  0448648 

"9? 

t8-  56  -50".  5  26 

.3247123 

43 

4°-  It'-  9".76 

.  0729952 

P^4 

7°-39-  34".46 

J33288O 

71 

S°-32'-6".76 

.  0442333 

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18° 

.3O9O/7O 

44- 

4° 

-S-  27.27 

.07/3391 

24 

7°-30 

./305262 

72 

2°-3o' 

.  O  43  6/94 

to? 

n°-8'-34'.28 

.2947622 

45 

4-° 

.0697565 

24-i 

7°-20-49" 

•  1278787 

73 

2°-27'-S6".7t 

.  O43O222 

// 

/6°-2f  '-49.09 

.2817325 

46 

3'-S4-46".9S 

.  0682424 

25 

7°  '2 

.  /25J332 

74 

2°-2s'-S6"75 

.  O4244I/ 

//  ' 

/S°-J3-  7".826 

•2697980 

47 

3'- 

49  -47"  23 

.  O667926 

1/2 

25? 

7°-  3'-3l".76 

.1228892 

75 

2°-S4' 

.  O4I8757 

12 

15° 

•2588/90 

48 

3°-4-s' 

.O654O3/ 

26 

6'-  55-  23".077 

.1205367 

76 

2°-S2-  6".3t 

.  O4/3249 

f2i 

/4°-24-' 

.2486899 

49 

3°-40-24".49 

.  O64O7O2 

26f 

6°-47-  32"83 

.  1/82739 

77 

2"  -SO'-  /5'.'Sg 

.0407885 

13 

13°-  50-  46".  /S 

.2393/57 

SO 

3°-36' 

.  O6279O5 

27 

6°-40 

.//6O929 

78 

2°->g'-S7"63 

.  O4O2659 

/Jf 

13°- 

zo' 

.  230  6  J  59 

51 

3°-3/'-45''S8 

.06/5609 

WES} 

FIG.  4 

I 

Mar.  4.  03  \  2 

Apr.  11.03  \        \                      \ 

,  PA.                   8'255 

HEETS.                                                      S3 

HNGHOUSE  ELECTRIC  &  MFG. 

3.     SAMPLE  PAGE  FROM  WESTINGHOUSE  BOOH 

Co.,  PITTS  BURG 

(  OF  STANDARD   DATA  St 

WEIGHTS  OF  ROUND  BAR    PER    INCH  OF  LENGTH. 


m 

O" 

r 

f 

^' 

^ 

J" 

6" 

7* 

8* 

ST 

10* 

//* 

f2* 

13* 

14? 

15* 

16* 

U* 

/8* 

o 

o 

0.  ?223 

0.891 

2.01 

3.57 

S.S8 

8.03 

'0.93 

14  28 

18.07 

22.31 

27.00 

32.13 

37. 

70 

43.72 

50.19 

57.10 

64.46 

72  27 

'/I6 

O.  OOOS7 

0.  2502 

0.9455 

2.09 

3.  68 

5.72 

8  20 

11.13 

14.  SO 

18.32 

22.59 

27.30 

-32  46 

38.  OS 

4-4.11 

50.61 

57.55 

64  94 

72.77 

'/* 

J    J03? 

0  2323 

I.  01 

2.18 

3  SO 

5.86 

8.37 

11.33 

'4.73 

18.58 

22  87 

2761 

32  So 

38.42 

4450 

51.03 

S7.99 

6S.4I 

73  28 

•-i/+- 

O  O07t 

0-3134 

/.07 

2.27 

3.91 

6.00 

8  54 

II  52 

/4.SS 

18.83 

23.  /S 

2792 

33.13 

38 

79 

4490 

51.45 

SS  45 

65.89 

73.  7g 

0.  0135 

0.3473 

1.13 

2.36 

4.03 

6.  IS 

~8.7I 

II. 

73 

/S./8 

19.09 

23.44 

28  24 

3348 

39 

16 

45.23 

S~87 

58  90 

66.37 

7429 

•2//6 

0  0217 

0.382? 

1  .19 

2  45 

4.14- 

S  30 

8.89 

11.93 

'5.41 

19.34 

23.72 

28  54 

33.  ft 

39 

53 

45.69 

52  30 

S9.3S 

66.85 

74  80 

Si 

0.  O3/2 

0  4-  202 

/  26 

2  54 

4-27 

6.45 

9.07 

12.13 

15.65 

/9.6I 

24.OI 

28.87 

34.17 

39 

90 

46  09 

52  73 

59.  8/ 

67.34 

7S.3/ 

3 

0.  0425 

04593 

1.33 

2.64 

4  39 

6.60 

9.25 

/2  34 

15.88 

19.87 

24.30 

29.19 

34.51 

40.28 

4649 

53  16 

60.27 

67  82 

75.81 

O  05S6 

0.5 

1  39 

2.73 

4~S! 

6.75 

9.43 

~2~S5 

ts./s 

2O.I3 

2460 

29  SO 

3486 

40. 

6S 

46.90 

5359 

60.73 

6831 

76.34 

0  0703 

0.5426 

/  46 

2  S3 

4  64- 

6  90 

961 

IZ.76 

1636 

20.40 

2489 

29.83 

35.21 

41. 

O3 

47  30 

54.02 

61-  /9 

68  SO 

76.  f  6 

•*"<? 

0  0868 

0.5869 

/  54- 

2.93 

4.77 

7.06 

9.73 

12.97 

16.60 

ZO  67 

25.13 

3O.I5 

35.56 

41.41 

47.71 

5446 

6/.6S 

69.29 

77.38 

"f|- 

o.  ion 

0.6329 

1-61 

3.03 

4-90 

7.22 

9.98 

13.18 

16.83 

20.93 

25.48 

3047  \ 

35  91 

41. 

79 

4S./2 

54.89 

62.11 

69  78 

77.90 

0.  1250 

0.  6807 

1.69 

3./4 

5.03 

7.38 

IO  16 

13.40 

/7.08 

21.21 

25.78 

30  80 

36  27 

42 

17 

48.53 

55.33 

62  58 

70.28 

78.42 

/J//6 

0   '467 

0.  7302 

1.76 

3.24 

5.17 

7.54 

10.35 

13.61 

17.32 

21  .48 

26.08 

31.12 

36.62 

42  56 

•48  94- 

5S.77 

63.  OS 

70.77 

78.94 

V* 

O.  1702 

0.  78/4 

1.84 

3  35 

S.30 

7.70 

/O.S4 

13  44 

17.57 

21.  76 

26.39 

31.46 

36.98 

42  94 

49  35 

5621 

63  SS 

7/.27 

79.47 

'S/I6 

0-  fOf3 

0.8344 

I  5' 

346 

5.44 

7  86 

IO.  74 

/4.0S 

/782 

22.03 

26  68 

31.79 

37.33 

43  33 

49.77 

56  66 

63  99 

71.77 

79.99 

M 

If 

20" 

21* 

2? 

23* 

24? 

25* 

26* 

27* 

28* 

29* 

30* 

3/* 

32* 

33* 

34* 

35* 

36~ 

o 

80.52 

89.  Z  2 

98.37 

107.96 

118.  OO 

128.48 

/  39.41 

150.78 

16261 

/  74.87 

187.59 

200.  75 

2/4.35 

228.41 

24291 

25785 

273.  24 

28908 

'/I6 

81.  OS 

89  7f 

9894 

IOS  57 

118-64 

129.  17 

140.10 

/  5  1.51 

163.36 

/7f.6S 

/88  39 

2OI.S8 

215.22 

229.30 

243.S2 

25879 

274.21 

I  g 

81  59 

30.34- 

99  54 

109 

.19 

119  28 

129.  82 

I4O.SI 

152.24- 

164-12 

176.44 

If9  21 

2O2.42 

2/6.09 

230  19 

244.75 

259.75 

275-24 

jSL 

82.12 

9090 

IOO.  13 

109.  ti 

119  93 

130.49 

141.51 

152.  97 

164  87 

177.  22 

I9OO2 

203.27 

216.95 

231.  09 

245.67 

260.  70 

276.  /t 

82.66 

91.47 

'00.  72 

110.43 

120  57 

131.  17 

/42.2I 

J5370 

/6S.63 

m  01 

>9o84 

204    // 

217  S3 

23/99 

246  60 

261  66 

277.16 

s/6 

83  19 

92.03 

101  .  32 

in 

Of 

/2l  22 

IS/.  85 

/42.92 

154.43 

/66.39 

nt.go 

/9I.  65 

204.95 

2/8.70 

232  f  9 

247  53 

262.61 

27  f  14 

3  8 

83  73 

92  60 

to/  .  91 

III 

67 

121  87 

'32.  53 

/4362 

155.  77 

167-  IS 

179  59 

/92  47 

205.80 

219  57 

233  79 

24S46 

26357 

279  13 

^^6 

84.27 

93.17 

102.51 

112 

29 

122  52 

'33  20 

14433 

155.90 

167.92 

18038 

'9329 

206.64 

220.44 

23469 

24938 

26452 

280  II 

84  82 

93.74 

/O3.  II 

112 

92 

I23./8 

133  89 

/4S04 

156  64 

/68  68 

I8/.  18 

194  II 

207.50 

22'  32 

235.60 

250.32. 

265  49 

281.  10 

9/H5 

85.36 

94.31 

/03.  71 

113 

SS 

'2334 

/34.S7 

/4-S  75 

/S738 

/  69.45 

/8I  97 

/94.  93 

2og  34 

222  20 

236  So 

251.  25 

26645 

232.09 

s  8 

8591 

!*a-S8 

/04.3I 

//A.  IS 

/2450 

'3  f  26 

146  4-7 

/St.  12 

170.22 

182.  77 

/9S.7S 

209  20 

313.08 

23742 

2SS./9 

267  42 

28309 

.."& 

86.45 

95  46 

104.91 

114 

ft 

125.  15 

135.94 

147.  /8 

'58  86 

170.99 

/83  57 

I96.S9 

2/0.  OS 

223.97 

23833 

253.  13 

26838 

284  OS 

87.00 

9604 

IOS.  52 

1/5.44 

12582 

'36   63 

14790 

159  61 

171.77 

184.37 

197  42 

210.91 

22485 

239.24 

254.07 

26935 

2tS  01 

»//6 

87  5b 

9662 

'06  .  >3 

/I6 

08 

126.48 

137.32 

I4g  62 

16036 

172.54 

>gS  /7 

19825 

211  .77 

22574 

240.15 

255.  01 

27032 

216  07 

7/b 

ffs  /: 

97.20 

106.73 

fl6 

72 

'27  14 

138.02 

149.34 

161.  IO 

173  32 

'SS.  97 

/99.0S 

2/2.63 

226.63 

241.  07 

255  96 

27/  29 

287.07 

'S//6 

88  66 

97  78 

107  35 

in  3S 

127  81 

138  71 

ISO.  O6 

'&'  SS 

174.  09 

>X6  7  f 

199.91 

2/3.49 

127  51 

241.  99 

256  SO 

272  27 

288.07 

The   we/ghh   in   fhis   table  are  based  o 
one  cubic  inch   of  steel  =  0.  2833  Ib. 

For    materials    of  her   than  sfeel    u 
the    multipliers   in    the    accompanying  t 

n 

se 
able. 

W'9.t-jh  f    m..n 

0  2779 

0.  98  IO 

E.. 

<  AMPLE  :    What  is    the    weight    of   a  solid  cast  iron 
Under,  S7t\~etia  X  I2O"  lam)? 

LUTION  :   In   the    table,    vertically    under  27".  and 
>monta//y    opposite  fa,  read  166  39  Ib 
rhe    required  weiaht  =  166.39  x  .  9191  x  120  -  18351  Ib. 

Cost   iron 

0  2604 

O    91  91 

CY 

V*'/t,~   Ura-l 

0    30!9 

1  .  Of9 

sc 

Copper 

O  3310 

1  .114 

hi 

Lead 

0.4106 

1    443 

Aluminum 

O  Oft) 

0,  3339 

Glali 

0    03*S 

0    JJlf 

\  1 

Auq  3.0S\ 

\ 

\ 

\ 

WESTINGHOUSE 

FIG.  41.     SAMPLE  PAGE 


ELECTRIC  &  MFG.  Co.,  PITTSBURG,  PA. 

FROM  WESTINGHOUSE  BOOK  OF  STANDARD  DATA  SHEETS. 


W.  I.  PIPE :  TAPS  &  REAMERS. 


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A 

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0.270 

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0.  113 

0.533 

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1.215 

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1.556 

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FIG.  42.     SAMPLE   PAGE  FROM  WESTINGHOUSE  BOOK  OF  STANDARD  DATA  SHEETS. 


55 


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Sizes   marked  •     are   kept  in    stock   by   manufactures  and  are    therefore   preferable   when 
new    lengths    an  required. 
Where   the   thread  length   is  entered  ,    the    bolt  thus    indicated  is  kept  in  stock   in   our                            r— 
Stortrooms  .                                                                                                     ,                     „ 
EXAMPLE:   Do    we  carry    in  stock    a    machine,  bolt    -^r  dia   X  7%  long,  and  what  is   the                       k_ 
length   of  the    thread  ?                                                                                                                 »                                              If 
Reading    opposite    %'{m    the   column   headed  DIA)   and  under    the  length   /5     we   find                              1 
entered   /f;     this   If  it    the   thread  length,  and   the  fact  that  it   is   entered  here   means   that   the                      \— 
bolt   required   is    in  stock. 

|-«  Length:  To  first 

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FIG.  43.     SAMPLE  PAGE  FROM   WESTINGHOUSE  BOOK  OF  STANDARD   DATA  SHEETS. 


one  item  to  another.  Without  guide  lines  it  is  easy  when  reading  across 
a  page  of  columns  to  get  on  to  the  wrong  line.  In  Fig.  41  modifications 
of  the  same  features  are  used;  the  vertical  columns  in  the  lower  half  of 
the  table  are  purposely  staggered  in  relation  to  those  in  the  upper  half, 
and  heavy-dash  guide  lines  are  again  employed.  In  Fig.  42  the  head- 
ings are  the  principal  feature;  they  are  arranged  in  striking  "groups," 
and  the  rulings  for  them  are  made  irregular — another  example  of  stag- 
gering. The  notable  feature  of  Fig.  43  is  the  manner  of  indicating  the 
bolt  lengths  in  the  horizontal  head  line,  f  to  15,  after  the  fashion  of  a 
graduated  scale;  here  also  the  use  of  guide  lines  is  an  important  feature, 
heavy  horizontal  and  vertical  lines  being  introduced  at  such  intervals 


as  to  make  it  easy  to  refer  quickly  to  any  required  size  of  bolt.  But 
perhaps  enough  has  been  said  to  show  that  in  making  up  sheets  of 
this  kind  there  is  room  for  the  exercise  of  a  great  deal  of  care  and 
ingenuity. 

155.  It  is  the  writer's  hope  that  the  engineering  profession  will  adopt 
the  size  and  style  of  standard  sheet  presented  here — or  some  other  on 
similar  lines — and  that  the  time  will  come  when  the  valuable  data  now 
worked  out  or  collected,  and  put  together  for  the  rather  selfish  use  of 
individuals  or  single  firms,  will  be  generously  distributed,  through  some 
such  channel  as  Engineering  News,  for  the  benefit  of  the  entire  engi- 
neering fraternity. 


CHAPTER   XII.     EXAMPLE    DRAWINGS. 


156.  Figs.  44  and  45  are  reproductions  of  actual  working  drawings 
belonging  to  the  type  that  this  dictionary  is  intended  to  govern — the 
"illustrated  specification."     They  are  introduced  here  merely  as  ex- 
amples of  the  writing  of  the  language,  and  not  because  they  deserve 
any  special  study  or  teach  any  particularly  valuable  lesson  in  them- 
selves.    Their  purpose  is  to  illustrate  in  a  general  way  the  dictionary 
features  covered  in  the  preceding  chapters. 

157.  The  only  way  that  any  man  can  hope  to  become  a  draftsman 
of  the  highest  type  is  to  make  drawings;  an  examination  of  the  drawings 
made  by  somebody  else  can  do  him  very  little  good.     It  is  a  compara- 


tively easy  matter  for  any  draftsman  or  drafting  room  to  adopt  such 
drawing  features  as  are  purely  mechanical — the  alphabet  of  lines,  styles 
of  lettering,  figures  and  dimensions,  projection,  sectioning,  the  finish 
mark  and  the  record  strip — but  it  is  only  by  the  persistent  exer- 
cise of  care,  common  sense,  and  good  judgment  in  the  actual  making 
of  drawings  that  the  individual  can  develop  into  the  high-class 
draftsman. 

158.  In  Fig.  45  certain  pieces  are  "  ite^njiumbered "  and  the  draw- 
ing carries  a  list  of  the  items  in  the  form  of  a  "bill  of  material,"  as  it  is 
generally  called.  Some  such  list  is  often  used  in  the  modern  drafting 


57 


sooe 


Note  that^U_the  \etyosed   vertical  comers 'must  in  rounded 


SPECIFIC  A  TIQN 

GENERAL  :    This  knowing _  table  is   to  con-Hun  6  lock  drawers  t  a  rack  to  hold  5  drawing  boards 

(size   of  boards  23~Kj/~xf)  a  swing  pocket  for  filing  drawings  in   envelopes  f3i2t  of  envelop*  23*31*) 

and  a  slide    to   carry    a  file   that   is    12'  long  X  I' wide. 
DIMENSIONS  and  CONSTRUCTION:    Every  dimension   that  is  enclosed  in  a  circle    must  be  as 

specified.     The  manufacturer   may   use   his  discretion    regarding   other   dimensions    to  insure 

good  construction.     The   table   must  rest  entirely    on   trie  *?•  I egs t  vith  2~  floor  clearance. 
MATERIALS  and  FINISH  :    All  visible    woodwork  except  the   top    to   be  of  oak,   of  handsome 

appearance   and  finished  with  one  coat  of  filler  and  two  coats  of  good    shellac   varnish, 

rubbed   smooth.  Invisible    woodwork   may    bt    either  pop/or    or  pine. 
THE   TOP :     To  be  of  the    besf  selected   white  pmet     kiln  dried,    free  from    knots  and  cracks, 

and   built   up   of    well  matched  strips,  not   exceeding  J  V**,   glued  together. 

To  be  securely   -fastened  to   the  legs    with  concealed  strips  and  dowels. 

To  be  flat  and  finished  in   natural  color   with    two   coats   of  best  yellow  shellac. 

LOCK   DRAWERS:    To  be  separated  from   one  another  by  means  of  solid  partitions  of  suitable 
thickness.     To  have  extension   as   shown,  so  that  they  may  be   safely  pulled  out  fo  the  full 
length.     Note   that  the   top  drawer  is    extra  deep. 

HARDWARE :    Each  drawer   to  be   fitted  with  a  Corbin   lock  and  two   keysj   a  drawer  pull  and 

a   card  holder       Two    master  keys  to  be   supplied    Nc  other  keys  reowred. 

The  swing  pocket  and  the   rack  door  each   to  have  a  good  qua/it y    spring  latch   and  a 

Corbtn   lock  also. 

All  the    hardware    to  be  very   substantial,    of  brass,    dull  finish 
No   two   locks   in  the   whole  supply  of  tobies    to  be  opened  w<th   the  same  key. 


Swing  Pocket 


2OO5 


THE  CARNEGIE    TECHNICAL  SCHOOLS.   Pittsburgh,  Pa.  U.S.A. 


Scale 


B-2005 


SINGLE  DRAWING  TABLE 

CjtBIMKT  SrYif 

o*  rut  SCHOOL  of  Afifufo  science 
Gmtral  Drawmq 


FIG.  44.     AN   EXAMPLE  WORKING  DRAWING  OF  THE  "ILLUSTRATED  SPECIFICATION  TYPE." 


I— **- 


Si' 


,4)  STUD  BOLT 


Standard  pinar, 
Standard  spindlf 


Four  fauallf   ipactd  stud  toffy 


T 


In  tfvs  drawing    tht  ports   that  art   sptctat 
fir   frit   motor-driirtn   latht  art  ittm  numbtnd 
and  listtd  in  frit  Bill  of  Mattnal 

farts    trot  bthna  to   tht  rtgular  btlt-dnrt 
art   "standard"  ana  art  not  stcttontd 


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28013 


THE   LOOSE   &  SHIPLEY  MACHINE    TOOL    COMPANY,     Cincinnati,   Ohio.   US. A 


Z8OI3 


24  MOTOR- DRIVEN  LATHE 
CHAIN  WHEEL  SPINDLE  SL£fV£ 

OeTML 


FIG.  45.     ANOTHER  EXAMPLE  WORKING  DRAWING  WITH   BILL  OF  MATERIAL. 


room,  the  form  and  contents  depending,  of  course,  upon  the  nature  of 
the  work  specified,  and  the  kind  of  information  required  by  the  shop. 
The  only  reason  for  directing  any  attention  here  to  the  bill  of  material 
is  to  advise  against  the  practice  of  using  ditto  marks  in  any  such  lists  on 


drawings.  The  bill  of  material  is  in  effect  a  collection  of  independent 
specifications,  and  each  specification  should  therefore  be  independently 
complete;  otherwise  it  will  happen  that  a  change  intended  to  affect  only 
one  item  will  go  through  as  affecting  all  those  ditto  marked  under  it. 


UNIVERSITY  OF  CALIFORNIA  LIBRARY, 
BERKELEY    . 

THIS  BOOK  IS  DUE  ON  THE  LAST  DATE 
STAMPED  BELOW 

Books  not  returned  on  time  are  •°W^°h?cre8Sing 
50c  per  volume  after  the  thirdly  over  ^  ^  ^  .^ 
to  $1.00  per  volume  after  tne 


^UG  4  1922 


20m-l,'22 


YE  0213 


,  •. 
v.  ' 


